Airway Resistance: 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.Airway Obstruction: Any hindrance to the passage of air into and out of the lungs.Plethysmography, Whole Body: 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)Lung Compliance: 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)Bronchoconstriction: Narrowing of the caliber of the BRONCHI, physiologically or as a result of pharmacological intervention.Airway Remodeling: The structural changes in the number, mass, size and/or composition of the airway tissues.Respiratory Mechanics: 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.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Lung Volume Measurements: Measurement of the amount of air that the lungs may contain at various points in the respiratory cycle.Drug Resistance: Diminished or failed response of an organism, disease or tissue to the intended effectiveness of a chemical or drug. It should be differentiated from DRUG TOLERANCE which is the progressive diminution of the susceptibility of a human or animal to the effects of a drug, as a result of continued administration.Respiratory Function Tests: Measurement of the various processes involved in the act of respiration: inspiration, expiration, oxygen and carbon dioxide exchange, lung volume and compliance, etc.Bronchoconstrictor Agents: Agents causing the narrowing of the lumen of a bronchus or bronchiole.Methacholine Chloride: 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)Bronchial Hyperreactivity: 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.Asthma: 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).Bronchi: 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.Respiratory System: 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.Drug Resistance, Microbial: The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).Drug Resistance, Bacterial: The ability of bacteria to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).Pulmonary Ventilation: The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.Inhalation: The act of BREATHING in.Bronchial Provocation Tests: 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.Rhinomanometry: Technique for measuring air pressure and the rate of airflow in the nasal cavity during respiration.Drug Resistance, Neoplasm: Resistance or diminished response of a neoplasm to an antineoplastic agent in humans, animals, or cell or tissue cultures.Nasal Obstruction: Any hindrance to the passage of air into and out of the nose. The obstruction may be unilateral or bilateral, and may involve any part of the NASAL CAVITY.Plethysmography: Recording of change in the size of a part as modified by the circulation in it.Functional Residual Capacity: 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.Air Pressure: 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.Histamine: 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.Spirometry: Measurement of volume of air inhaled or exhaled by the lung.Bronchodilator Agents: Agents that cause an increase in the expansion of a bronchus or bronchial tubes.Drug Resistance, Multiple: Simultaneous resistance to several structurally and functionally distinct drugs.Respiratory Physiological Phenomena: Physiological processes and properties of the RESPIRATORY SYSTEM as a whole or of any of its parts.Rhinometry, Acoustic: Diagnostic measurement of the nose and its cavity through acoustic reflections. Used to measure nasal anatomical landmarks, nasal septal deviation, and nasal airway changes in response to allergen provocation tests (NASAL PROVOCATION TESTS).Nasal Decongestants: Drugs designed to treat inflammation of the nasal passages, generally the result of an infection (more often than not the common cold) or an allergy related condition, e.g., hay fever. The inflammation involves swelling of the mucous membrane that lines the nasal passages and results in inordinate mucus production. The primary class of nasal decongestants are vasoconstrictor agents. (From PharmAssist, The Family Guide to Health and Medicine, 1993)Disease Resistance: The capacity of an organism to defend itself against pathological processes or the agents of those processes. This most often involves innate immunity whereby the organism responds to pathogens in a generic way. The term disease resistance is used most frequently when referring to plants.Respiration: 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).Bronchoalveolar Lavage Fluid: 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.Vascular Resistance: The force that opposes the flow of BLOOD through a vascular bed. It is equal to the difference in BLOOD PRESSURE across the vascular bed divided by the CARDIAC OUTPUT.Nose: A part of the upper respiratory tract. It contains the organ of SMELL. The term includes the external nose, the nasal cavity, and the PARANASAL SINUSES.Administration, Inhalation: The administration of drugs by the respiratory route. It includes insufflation into the respiratory tract.Tidal Volume: The volume of air inspired or expired during each normal, quiet respiratory cycle. Common abbreviations are TV or V with subscript T.Oscillometry: The measurement of frequency or oscillation changes.Forced Expiratory Volume: 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.Ipratropium: 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.Albuterol: 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.Drug Resistance, Viral: The ability of viruses to resist or to become tolerant to chemotherapeutic agents or antiviral agents. This resistance is acquired through gene mutation.Drug Resistance, Multiple, Bacterial: The ability of bacteria to resist or to become tolerant to several structurally and functionally distinct drugs simultaneously. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).Respiratory Hypersensitivity: A form of hypersensitivity affecting the respiratory tract. It includes ASTHMA and RHINITIS, ALLERGIC, SEASONAL.Epiglottis: A thin leaf-shaped cartilage that is covered with LARYNGEAL MUCOSA and situated posterior to the root of the tongue and HYOID BONE. During swallowing, the epiglottis folds back over the larynx inlet thus prevents foods from entering the airway.Nasal Provocation Tests: Application of allergens to the nasal mucosa. Interpretation includes observation of nasal symptoms, rhinoscopy, and rhinomanometry. Nasal provocation tests are used in the diagnosis of nasal hypersensitivity, including RHINITIS, ALLERGIC, SEASONAL.Aerosols: 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.Nasal Cavity: 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.Intubation, Intratracheal: 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.Bronchial Spasm: Spasmodic contraction of the smooth muscle of the bronchi.Positive-Pressure Respiration: 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.Respiratory Muscles: These include the muscles of the DIAPHRAGM and the INTERCOSTAL MUSCLES.Clemastine: A histamine H1 antagonist used as the hydrogen fumarate in hay fever, rhinitis, allergic skin conditions, and pruritus. It causes drowsiness.Anti-Bacterial Agents: Substances that reduce the growth or reproduction of BACTERIA.Maximal Expiratory Flow-Volume Curves: Curves depicting MAXIMAL EXPIRATORY FLOW RATE, in liters/second, versus lung inflation, in liters or percentage of lung capacity, during a FORCED VITAL CAPACITY determination. Common abbreviation is MEFV.Mouth Breathing: Abnormal breathing through the mouth, usually associated with obstructive disorders of the nasal passages.Work of Breathing: 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)Airway Management: Evaluation, planning, and use of a range of procedures and airway devices for the maintenance or restoration of a patient's ventilation.Pharynx: A funnel-shaped fibromuscular tube that conducts food to the ESOPHAGUS, and air to the LARYNX and LUNGS. It is located posterior to the NASAL CAVITY; ORAL CAVITY; and LARYNX, and extends from the SKULL BASE to the inferior border of the CRICOID CARTILAGE anteriorly and to the inferior border of the C6 vertebra posteriorly. It is divided into the NASOPHARYNX; OROPHARYNX; and HYPOPHARYNX (laryngopharynx).Respiratory Mucosa: The mucous membrane lining the RESPIRATORY TRACT, including the NASAL CAVITY; the LARYNX; the TRACHEA; and the BRONCHI tree. The respiratory mucosa consists of various types of epithelial cells ranging from ciliated columnar to simple squamous, mucous GOBLET CELLS, and glands containing both mucous and serous cells.Thyroid Cartilage: The largest cartilage of the larynx consisting of two laminae fusing anteriorly at an acute angle in the midline of the neck. The point of fusion forms a subcutaneous projection known as the Adam's apple.Muscle, Smooth: Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)Snoring: Rough, noisy breathing during sleep, due to vibration of the uvula and soft palate.Microbial Sensitivity Tests: Any tests that demonstrate the relative efficacy of different chemotherapeutic agents against specific microorganisms (i.e., bacteria, fungi, viruses).Total Lung Capacity: 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.Lung Diseases, Obstructive: Any disorder marked by obstruction of conducting airways of the lung. AIRWAY OBSTRUCTION may be acute, chronic, intermittent, or persistent.Forced Expiratory Flow Rates: The rate of airflow measured during a FORCED VITAL CAPACITY determination.Sleep Apnea Syndromes: Disorders characterized by multiple cessations of respirations during sleep that induce partial arousals and interfere with the maintenance of sleep. Sleep apnea syndromes are divided into central (see SLEEP APNEA, CENTRAL), obstructive (see SLEEP APNEA, OBSTRUCTIVE), and mixed central-obstructive types.Sleep Apnea, Obstructive: A disorder characterized by recurrent apneas during sleep despite persistent respiratory efforts. It is due to upper airway obstruction. The respiratory pauses may induce HYPERCAPNIA or HYPOXIA. Cardiac arrhythmias and elevation of systemic and pulmonary arterial pressures may occur. Frequent partial arousals occur throughout sleep, resulting in relative SLEEP DEPRIVATION and daytime tiredness. Associated conditions include OBESITY; ACROMEGALY; MYXEDEMA; micrognathia; MYOTONIC DYSTROPHY; adenotonsilar dystrophy; and NEUROMUSCULAR DISEASES. (From Adams et al., Principles of Neurology, 6th ed, p395)Vital Capacity: The volume of air that is exhaled by a maximal expiration following a maximal inspiration.Guinea Pigs: 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.Mucus: The viscous secretion of mucous membranes. It contains mucin, white blood cells, water, inorganic salts, and exfoliated cells.Nasal Mucosa: 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.Helium: 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)Respiratory Sounds: Noises, normal and abnormal, heard on auscultation over any part of the RESPIRATORY TRACT.Methacholine Compounds: A group of compounds that are derivatives of beta-methylacetylcholine (methacholine).Cromolyn Sodium: 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.Sleep: A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility.Pulmonary Gas Exchange: The exchange of OXYGEN and CARBON DIOXIDE between alveolar air and pulmonary capillary blood that occurs across the BLOOD-AIR BARRIER.Cough: 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: Altered reactivity to an antigen, which can result in pathologic reactions upon subsequent exposure to that particular antigen.Eosinophils: 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.Respiration, Artificial: 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).Sneezing: The sudden, forceful, involuntary expulsion of air from the NOSE and MOUTH caused by irritation to the MUCOUS MEMBRANES of the upper RESPIRATORY TRACT.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Disease Models, Animal: 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.Pulmonary Emphysema: Enlargement of air spaces distal to the TERMINAL BRONCHIOLES where gas-exchange normally takes place. This is usually due to destruction of the alveolar wall. Pulmonary emphysema can be classified by the location and distribution of the lesions.Tetracycline Resistance: Nonsusceptibility of bacteria to the action of TETRACYCLINE which inhibits aminoacyl-tRNA binding to the 30S ribosomal subunit during protein synthesis.Mice, Inbred BALB CAtropine Derivatives: Analogs and derivatives of atropine.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Bronchitis: Inflammation of the large airways in the lung including any part of the BRONCHI, from the PRIMARY BRONCHI to the TERTIARY BRONCHI.Trachea: The cartilaginous and membranous tube descending from the larynx and branching into the right and left main bronchi.Pressure: 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)Models, Biological: 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.Wakefulness: A state in which there is an enhanced potential for sensitivity and an efficient responsiveness to external stimuli.Exhalation: The act of BREATHING out.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Lung Diseases: Pathological processes involving any part of the LUNG.Pneumonia: Infection of the lung often accompanied by inflammation.Plant Diseases: Diseases of plants.Ascaris suum: A species of parasitic nematode usually found in domestic pigs and a few other animals. Human infection can also occur, presumably as result of handling pig manure, and can lead to intestinal obstruction.Penicillin Resistance: Nonsusceptibility of an organism to the action of penicillins.Mice, Inbred C57BLPulmonary Disease, Chronic Obstructive: A disease of chronic diffuse irreversible airflow obstruction. Subcategories of COPD include CHRONIC BRONCHITIS and PULMONARY EMPHYSEMA.Respiratory System Agents: Drugs used for their effects on the respiratory system.Maximal Expiratory Flow Rate: The airflow rate measured during the first liter expired after the first 200 ml have been exhausted during a FORCED VITAL CAPACITY determination. Common abbreviations are MEFR, FEF 200-1200, and FEF 0.2-1.2.Residual Volume: The volume of air remaining in the LUNGS at the end of a maximal expiration. Common abbreviation is RV.Tongue: A muscular organ in the mouth that is covered with pink tissue called mucosa, tiny bumps called papillae, and thousands of taste buds. The tongue is anchored to the mouth and is vital for chewing, swallowing, and for speech.Dogs: 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)Inflammation: 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.Elasticity: Resistance and recovery from distortion of shape.Ovalbumin: An albumin obtained from the white of eggs. It is a member of the serpin superfamily.Polysomnography: Simultaneous and continuous monitoring of several parameters during sleep to study normal and abnormal sleep. The study includes monitoring of brain waves, to assess sleep stages, and other physiological variables such as breathing, eye movements, and blood oxygen levels which exhibit a disrupted pattern with sleep disturbances.Drug Resistance, Fungal: The ability of fungi to resist or to become tolerant to chemotherapeutic agents, antifungal agents, or antibiotics. This resistance may be acquired through gene mutation.Vocal Cord Paralysis: Congenital or acquired paralysis of one or both VOCAL CORDS. This condition is caused by defects in the CENTRAL NERVOUS SYSTEM, the VAGUS NERVE and branches of LARYNGEAL NERVES. Common symptoms are VOICE DISORDERS including HOARSENESS or APHONIA.Atropine: An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.Ventilators, Mechanical: Mechanical devices used to produce or assist pulmonary ventilation.Hyperventilation: 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.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Pulmonary Alveoli: 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.Pulmonary Circulation: The circulation of the BLOOD through the LUNGS.Allergens: Antigen-type substances that produce immediate hypersensitivity (HYPERSENSITIVITY, IMMEDIATE).Humidity: A measure of the amount of WATER VAPOR in the air.Sleep Stages: Periods of sleep manifested by changes in EEG activity and certain behavioral correlates; includes Stage 1: sleep onset, drowsy sleep; Stage 2: light sleep; Stages 3 and 4: delta sleep, light sleep, deep sleep, telencephalic sleep.Pulmonary Edema: Excessive accumulation of extravascular fluid in the lung, an indication of a serious underlying disease or disorder. Pulmonary edema prevents efficient PULMONARY GAS EXCHANGE in the PULMONARY ALVEOLI, and can be life-threatening.Mandibular Advancement: Moving a retruded mandible forward to a normal position. It is commonly performed for malocclusion and retrognathia. (From Jablonski's Dictionary of Dentistry, 1992)Thorax: 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)Bacterial Proteins: Proteins found in any species of bacterium.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.beta-Lactam Resistance: Nonsusceptibility of bacteria to the action of the beta-lactam antibiotics. Mechanisms responsible for beta-lactam resistance may be degradation of antibiotics by BETA-LACTAMASES, failure of antibiotics to penetrate, or low-affinity binding of antibiotics to targets.Reference Values: 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.Laryngeal Masks: A type of oropharyngeal airway that provides an alternative to endotracheal intubation and standard mask anesthesia in certain patients. It is introduced into the hypopharynx to form a seal around the larynx thus permitting spontaneous or positive pressure ventilation without penetration of the larynx or esophagus. It is used in place of a facemask in routine anesthesia. The advantages over standard mask anesthesia are better airway control, minimal anesthetic gas leakage, a secure airway during patient transport to the recovery area, and minimal postoperative problems.Carbon Dioxide: A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.Positive-Pressure Respiration, Intrinsic: 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)Immunity, Innate: The capacity of a normal organism to remain unaffected by microorganisms and their toxins. It results from the presence of naturally occurring ANTI-INFECTIVE AGENTS, constitutional factors such as BODY TEMPERATURE and immediate acting immune cells such as NATURAL KILLER CELLS.Continuous Positive Airway Pressure: A technique of respiratory therapy, in either spontaneously breathing or mechanically ventilated patients, in which airway pressure is maintained above atmospheric pressure throughout the respiratory cycle by pressurization of the ventilatory circuit. (On-Line Medical Dictionary [Internet]. Newcastle upon Tyne(UK): The University Dept. of Medical Oncology: The CancerWEB Project; c1997-2003 [cited 2003 Apr 17]. Available from: http://cancerweb.ncl.ac.uk/omd/)Resistance Training: A type of strength-building exercise program that requires the body muscle to exert a force against some form of resistance, such as weight, stretch bands, water, or immovable objects. Resistance exercise is a combination of static and dynamic contractions involving shortening and lengthening of skeletal muscles.Sympatholytics: Drugs that inhibit the actions of the sympathetic nervous system by any mechanism. The most common of these are the ADRENERGIC ANTAGONISTS and drugs that deplete norepinephrine or reduce the release of transmitters from adrenergic postganglionic terminals (see ADRENERGIC AGENTS). Drugs that act in the central nervous system to reduce sympathetic activity (e.g., centrally acting alpha-2 adrenergic agonists, see ADRENERGIC ALPHA-AGONISTS) are included here.Mice, Knockout: 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.R Factors: A class of plasmids that transfer antibiotic resistance from one bacterium to another by conjugation.Anesthesia, General: Procedure in which patients are induced into an unconscious state through use of various medications so that they do not feel pain during surgery.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Epithelial Cells: Cells that line the inner and outer surfaces of the body by forming cellular layers (EPITHELIUM) or masses. Epithelial cells lining the SKIN; the MOUTH; the NOSE; and the ANAL CANAL derive from ectoderm; those lining the RESPIRATORY SYSTEM and the DIGESTIVE SYSTEM derive from endoderm; others (CARDIOVASCULAR SYSTEM and LYMPHATIC SYSTEM) derive from mesoderm. Epithelial cells can be classified mainly by cell shape and function into squamous, glandular and transitional epithelial cells.Cytokines: 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.Muscle Contraction: A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.Acetanilides: Compounds based on N-phenylacetamide, that are similar in structure to 2-PHENYLACETAMIDES. They are precursors of many other compounds. They were formerly used as ANALGESICS and ANTIPYRETICS, but often caused lethal METHEMOGLOBINEMIA.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Escherichia coli: 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.Cross-Over Studies: 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)P-Glycoprotein: A 170-kDa transmembrane glycoprotein from the superfamily of ATP-BINDING CASSETTE TRANSPORTERS. It serves as an ATP-dependent efflux pump for a variety of chemicals, including many ANTINEOPLASTIC AGENTS. Overexpression of this glycoprotein is associated with multidrug resistance (see DRUG RESISTANCE, MULTIPLE).Ampicillin Resistance: Nonsusceptibility of a microbe to the action of ampicillin, a penicillin derivative that interferes with cell wall synthesis.Chloramphenicol Resistance: Nonsusceptibility of bacteria to the action of CHLORAMPHENICOL, a potent inhibitor of protein synthesis in the 50S ribosomal subunit where amino acids are added to nascent bacterial polypeptides.Blood Gas Analysis: Measurement of oxygen and carbon dioxide in the blood.Hemodynamics: The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.Oxygen: An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.Reflex: An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.Plasmids: Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.Vagus Nerve: The 10th cranial nerve. The vagus is a mixed nerve which contains somatic afferents (from skin in back of the ear and the external auditory meatus), visceral afferents (from the pharynx, larynx, thorax, and abdomen), parasympathetic efferents (to the thorax and abdomen), and efferents to striated muscle (of the larynx and pharynx).Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Tetracycline: A naphthacene antibiotic that inhibits AMINO ACYL TRNA binding during protein synthesis.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Paralysis: A general term most often used to describe severe or complete loss of muscle strength due to motor system disease from the level of the cerebral cortex to the muscle fiber. This term may also occasionally refer to a loss of sensory function. (From Adams et al., Principles of Neurology, 6th ed, p45)Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Cystic Fibrosis: An autosomal recessive genetic disease of the EXOCRINE GLANDS. It is caused by mutations in the gene encoding the CYSTIC FIBROSIS TRANSMEMBRANE CONDUCTANCE REGULATOR expressed in several organs including the LUNG, the PANCREAS, the BILIARY SYSTEM, and the SWEAT GLANDS. Cystic fibrosis is characterized by epithelial secretory dysfunction associated with ductal obstruction resulting in AIRWAY OBSTRUCTION; chronic RESPIRATORY INFECTIONS; PANCREATIC INSUFFICIENCY; maldigestion; salt depletion; and HEAT PROSTRATION.Genes, Bacterial: The functional hereditary units of BACTERIA.Acetylcholine: A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.Cells, Cultured: 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.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Conjugation, Genetic: A parasexual process in BACTERIA; ALGAE; FUNGI; and ciliate EUKARYOTA for achieving exchange of chromosome material during fusion of two cells. In bacteria, this is a uni-directional transfer of genetic material; in protozoa it is a bi-directional exchange. In algae and fungi, it is a form of sexual reproduction, with the union of male and female gametes.Methicillin Resistance: Non-susceptibility of a microbe to the action of METHICILLIN, a semi-synthetic penicillin derivative.Erythromycin: A bacteriostatic antibiotic macrolide produced by Streptomyces erythreus. Erythromycin A is considered its major active component. In sensitive organisms, it inhibits protein synthesis by binding to 50S ribosomal subunits. This binding process inhibits peptidyl transferase activity and interferes with translocation of amino acids during translation and assembly of proteins.Insulin: A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Electromyography: Recording of the changes in electric potential of muscle by means of surface or needle electrodes.Cell Line, Tumor: A cell line derived from cultured tumor cells.Treatment Outcome: 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.Cephalosporin Resistance: Non-susceptibility of an organism to the action of the cephalosporins.Dyspnea: Difficult or labored breathing.Reproducibility of Results: 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.Propranolol: A widely used non-cardioselective beta-adrenergic antagonist. Propranolol has been used for MYOCARDIAL INFARCTION; ARRHYTHMIA; ANGINA PECTORIS; HYPERTENSION; HYPERTHYROIDISM; MIGRAINE; PHEOCHROMOCYTOMA; and ANXIETY but adverse effects instigate replacement by newer drugs.Polymerase Chain Reaction: 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.Posture: The position or attitude of the body.Infant, Newborn: An infant during the first month after birth.
Nitric oxide limits the eicosanoid-dependent bronchoconstriction and hypotension induced by endothelin-1 in the guinea-pig. (1/1568)
1. This study attempts to investigate if endogenous nitric oxide (NO) can modulate the eicosanoid-releasing properties of intravenously administered endothelin-1 (ET-1) in the pulmonary and circulatory systems in the guinea-pig. 2. The nitric oxide synthase blocker N(omega)-nitro-L-arginine methyl ester (L-NAME; 300 microM; 30 min infusion) potentiated, in an L-arginine sensitive fashion, the release of thromboxane A2 (TxA2) stimulated by ET-1, the selective ET(B) receptor agonist IRL 1620 (Suc-[Glu9,Ala11,15]-ET-1(8-21)) or bradykinin (BK) (5, 50 and 50 nM, respectively, 3 min infusion) in guinea-pig isolated and perfused lungs. 3. In anaesthetized and ventilated guinea-pigs intravenous injection of ET-1 (0.1-1.0 nmol kg(-1)), IRL 1620 (0.2-1.6 nmol kg(-1)), BK (1.0-10.0 nmol kg(-1)) or U 46619 (0.2-5.7 nmol kg(-1)) each induced dose-dependent increases in pulmonary insufflation pressure (PIP). Pretreatment with L-NAME (5 mg kg(-1)) did not change basal PIP, but increased, in L-arginine sensitive manner, the magnitude of the PIP increases (in both amplitude and duration) triggered by each of the peptides (at 0.25, 0.4 and 1.0 nmol kg(-1), respectively), without modifying bronchoconstriction caused by U 46619 (0.57 nmol kg(-1)). 4. The increases in PIP induced by ET-1, IRL 1620 (0.25 and 0.4 nmol kg(-1), respectively) or U 46619 (0.57 nmol kg(-1)) were accompanied by rapid and transient increases of mean arterial blood pressure (MAP). Pretreatment with L-NAME (5 mg kg(-1); i.v. raised basal MAP persistently and, under this condition, subsequent administration of ET-1 or IRL 1620, but not of U-46619, induced hypotensive responses which were prevented by pretreatment with the cyclo-oxygenase inhibitor indomethacin. 5. Thus, endogenous NO appears to modulate ET-1-induced bronchoconstriction and pressor effects in the guinea-pig by limiting the peptide's ability to induce, possibly via ET(B) receptors, the release of TxA2 in the lungs and of vasodilatory prostanoids in the systemic circulation. Furthermore, it would seem that these eicosanoid-dependent actions of ET-1 in the pulmonary system and on systemic arterial resistance in this species are physiologically dissociated. (+info)Dose-response slope of forced oscillation and forced expiratory parameters in bronchial challenge testing. (2/1568)
In population studies, the provocative dose (PD) of bronchoconstrictor causing a significant decrement in lung function cannot be calculated for most subjects. Dose-response curves for carbachol were examined to determine whether this relationship can be summarized by means of a continuous index likely to be calculable for all subjects, namely the two-point dose response slope (DRS) of mean resistance (Rm) and resistance at 10 Hz (R10) measured by the forced oscillation technique (FOT). Five doses of carbachol (320 microg each) were inhaled by 71 patients referred for investigation of asthma (n=16), chronic cough (n=15), nasal polyposis (n=8), chronic rhinitis (n=8), dyspnoea (n=8), urticaria (n=5), post-anaphylactic shock (n=4) and miscellaneous conditions (n=7). FOT resistance and forced expiratory volume in one second (FEV1) were measured in close succession. The PD of carbachol leading to a fall in FEV1 > or = 20% (PD20) or a rise in Rm or R10 > or = 47% (PD47,Rm and PD47,R10) were calculated by interpolation. DRS for FEV1 (DRSFEV1), Rm (DRSRm) and R10 (DRSR10) were obtained as the percentage change at last dose divided by the total dose of carbachol. The sensitivity (Se) and specificity (Sp) of DRSRm, DRS10 delta%Rm and delta%R10 in detecting spirometric bronchial hyperresponsiveness (BHR, fall in FEV1 > or = 20%) were assessed by receiver operating characteristic (ROC) curves. There were 23 (32%) "spirometric" reactors. PD20 correlated strongly with DRSFEV1 (r=-0.962; p=0.0001); PD47,Rm correlated significantly with DRSRm (r=-0.648; p=0.0001) and PD47,R10 with DRSR10 (r=-0.552; p=0.0001). DRSFEV1 correlated significantly with both DRSRm (r=0.700; p=0.0001) and DRSR10 (r=0.784; p=0.0001). The Se and Sp of the various FOT indices to correctly detect spirometric BHR were as follows: DRSRm: Se=91.3%, Sp=81.2%; DRSR10: Se=91.3%, Sp=95.8%; delta%Rm: Se=86.9%, Sp=52.1%; and delta%R10: Se=91.3%, Sp=58.3%. Dose-response slopes of indices of forced oscillation technique resistance, especially the dose-response slope of resistance at 10Hz are proposed as simple quantitative indices of bronchial responsiveness which can be calculated for all subjects and that may be useful in occupational epidemiology. (+info)Bradykinin-induced bronchospasm in the rat in vivo: a role for nitric oxide modulation. (3/1568)
Bradykinin has an important role in asthma pathogenesis, but its site of action is unclear. It was previously reported by the authors that bradykinin causes a dose-dependent reduction in dynamic compliance but little change in total lung resistance. This suggested that bradykinin may have a preferential effect in the distant lung. The purpose of the current investigation was to better characterize the effects of bradykinin on pulmonary resistance in rodents and explore the role of nitric oxide release in modulating the effect of bradykinin. Airway constriction was induced in the rats by aerosol administration of bradykinin with or without treatments with the inhaled bradykinin-2 receptor antagonist, Hoe 140 or the nitric oxide synthase inhibitors N(G)-nitro-L-arginine methylester or N(G)-monomethyl-L-arginine. Total lung resistance was partitioned into tissue and airway resistance by using the alveolar capsule method. Bradykinin induced a significant increase in both resistances. Hoe 140 abolished the response to bradykinin. The nitric oxide synthase inhibitors enhanced the bronchoconstricting response. In conclusion, the bradykinin response in the rats was not only localized to conducting airways but also involved a relatively selective tissue reaction. Bradykinin-induced bronchospasm in the rat is solely due to activation of bradykinin-2 receptor. Further, it was shown that nitric oxide significantly modulates the bronchospasm caused by bradykinin, suggesting that nitric oxide is an important modulator of airways responsiveness to bradykinin. (+info)Acinar flow irreversibility caused by perturbations in reversible alveolar wall motion. (4/1568)
Mixing associated with "stretch-and-fold" convective flow patterns has recently been demonstrated to play a potentially important role in aerosol transport and deposition deep in the lung (J. P. Butler and A. Tsuda. J. Appl. Physiol. 83: 800-809, 1997), but the origin of this potent mechanism is not well characterized. In this study we hypothesized that even a small degree of asynchrony in otherwise reversible alveolar wall motion is sufficient to cause flow irreversibility and stretch-and-fold convective mixing. We tested this hypothesis using a large-scale acinar model consisting of a T-shaped junction of three short, straight, square ducts. The model was filled with silicone oil, and alveolar wall motion was simulated by pistons in two of the ducts. The pistons were driven to generate a low-Reynolds-number cyclic flow with a small amount of asynchrony in boundary motion adjusted to match the degree of geometric (as distinguished from pressure-volume) hysteresis found in rabbit lungs (H. Miki, J. P. Butler, R. A. Rogers, and J. Lehr. J. Appl. Physiol. 75: 1630-1636, 1993). Tracer dye was introduced into the system, and its motion was monitored. The results showed that even a slight asynchrony in boundary motion leads to flow irreversibility with complicated swirling tracer patterns. Importantly, the kinematic irreversibility resulted in stretching of the tracer with narrowing of the separation between adjacent tracer lines, and when the cycle-by-cycle narrowing of lateral distance reached the slowly growing diffusion distance of the tracer, mixing abruptly took place. This coupling of evolving convective flow patterns with diffusion is the essence of the stretch-and-fold mechanism. We conclude that even a small degree of boundary asynchrony can give rise to stretch-and-fold convective mixing, thereby leading to transport and deposition of fine and ultrafine aerosol particles deep in the lung. (+info)A genome-wide screen for asthma-associated quantitative trait loci in a mouse model of allergic asthma. (5/1568)
Asthma is the most common illness of childhood, affecting one child in seven in the UK. Asthma has a genetic basis, but genetic studies of asthma in humans are confounded by uncontrolled environmental factors, varying penetrance and phenotypic pleiotropy. An animal model of asthma would offer controlled exposure, limited and consistent genetic variation, and unlimited size of sibships. Following immunization and subsequent challenge with ovalbumin, the Biozzi BP2 mouse shows features of asthma, including airway inflammation, eosinophil infiltration and non-specific bronchial responsiveness. In order to identify genetic loci influencing these traits, a cross was made between BP2 and BALB/c mice, and a genome-wide screen carried out in the F2progeny of the F1intercross. Five potentially linked loci were identified, four of which corresponded to human regions of syntenic homology that previously have shown linkage to asthma-associated traits. (+info)Pulmonary expression of interleukin-13 causes inflammation, mucus hypersecretion, subepithelial fibrosis, physiologic abnormalities, and eotaxin production. (6/1568)
Interleukin (IL)-13 is a pleiotropic cytokine produced in large quantities by activated CD4(+) Th2 lymphocytes. To define further its potential in vivo effector functions, the Clara cell 10-kDa protein promoter was used to express IL-13 selectively in the lung, and the phenotype of the resulting transgenic mice was characterized. In contrast to transgene-negative littermates, the lungs of transgene-positive mice contained an inflammatory response around small and large airways and in the surrounding parenchyma. It was mononuclear in nature and contained significant numbers of eosinophils and enlarged and occasionally multinucleated macrophages. Airway epithelial cell hypertrophy, mucus cell metaplasia, the hyperproduction of neutral and acidic mucus, the deposition of Charcot-Leyden-like crystals, and subepithelial airway fibrosis were also prominently noted. Eotaxin protein and mRNA were also present in large quantities in the lungs of the transgene-positive, but not the transgene-negative, mice. IL-4, IL-5, granulocyte-macrophage colony-stimulating factor, and monocyte chemoattractant protein-5 were not similarly detected. Physiological evaluations revealed significant increases in baseline airways resistance and airways hyperresponsiveness (AHR) to methacholine in transgene-positive animals. Thus, the targeted pulmonary expression of IL-13 causes a mononuclear and eosinophilic inflammatory response, mucus cell metaplasia, the deposition of Charcot-Leyden-like crystals, airway fibrosis, eotaxin production, airways obstruction, and nonspecific AHR. IL-13 may play an important role in the pathogenesis of similar responses in asthma or other Th2-polarized tissue responses. (+info)Respiratory mechanics in airways obstruction associated with inspiratory dyspnoea. (7/1568)
Inspiratory muscle strength and the flow and elastic pressure opposing inspiration were measured in seven patients with severe airways obstruction who found inspiration difficult at rest. A comparison was made of measurements obtained from seven normal subjects and five patients with airways obstruction not experiencing inspiratory dyspnoea at rest. Measurements were also obtained when inspiratory dyspnoea was induced in the normal subjects by adding an inspiratory resistance or by voluntarily increasing lung volume. Compared with the controls the inspiratory muscle strength of the patients was reduced but was not significantly less than that of the patients without inspiratory dyspnoea. The pressure required to produce inspiratory flow was significantly greater when inspiratory dyspnoea was present (P = 0-01). However, there was considerable overlap in the pressures of those with and without inspiratory dyspnoea. A better relationship was obtained when muscle strength was considered. The ratio of inspiratory muscle strength to the pressure required to produce flow was 0-24 +/- 0-07 (mean +/- SD) in patient with inspiratory dyspnoea, 0-10 +/- 0-03 in patients without inspiratory dyspnoea, and 0-033 +/- 0-019 in normal subjects. There was no overlap between the two patient groups. The ratios of the normal subjects were increased when inspiratory dyspnoea was induced and, with the exception of two cases, were all above those obtained when inspiratory dyspnoea was absent. Inspiratory dyspnoea was experienced with lower ratios in the normals than in the patients with airways obstruction. (+info)Physiologic basis and interpretation of common indices of respiratory mechanical function. (8/1568)
Tests of pulmonary mechanical function may be used in determining the prominent site of pulmonary reaction to intervention. Responses may be localized from a knowledge of changes in lung resistance and compliance. A peripheral airway or parenchymal response is characterized by a decrease in lung compliance. A central airway reaction is characterized by an increase in pulmonary resistance. In mixed reactions both parameters may change. In this communication some of the physiologic determinants of pulmonary resistance and compliance are discussed and examples of localized responses given. (+info)Upper airway resistance[edit]. Airway resistance increases by about 230% during NREM sleep. Elastic and flow resistive ... Upper airway function[edit]. Upper airway resistance is expected to be highest during REM sleep because of atonia of the ... Upper airway resistance syndrome[edit]. This section needs expansion. You can help by adding to it. (December 2010) ... Main article: Upper airway resistance syndrome. Obstructive sleep apnea (including hypopnea) syndrome[edit]. Main article: ...
The upper airway resistance syndrome". Chest. 104 (3): 781-7. doi:10.1378/chest.104.3.781. PMID 8365289. Attribution of the ... Following this work, he went on to describe the presence of elevated upper airway resistance in children in 1982, emphasizing ... "upper airway resistance syndrome" (UARS) in adults. Finally, working in collaboration with Dr. William C. Dement, Guilleminault ... "Sleep-induced apnea syndrome, a surgical procedure to establish patency of the upper airway during sleep". "Sleep-induced apnea ...
... increases with any airway resistance. Things that may increase PIP could be increased secretions, ...
Upper airway resistance syndrome may also be implicated. Treatment may involve investigation, reassurance and explanation, and ... "Functional somatic syndromes, anxiety disorders and the upper airway: A matter of paradigms". Sleep Medicine Reviews. 15 (6). ...
... in 2014 granted pre-market approval for an upper airway stimulation system that senses respiration and delivers mild electrical ... Automatic positive airway pressure, or automatic positive airway pressure, also known as "Auto CPAP", incorporates pressure ... Surgical treatments to modify airway anatomy, known as sleep surgery, are varied and must be tailored to the specific airway ... Continuous positive airway pressure (CPAP) is effective for both moderate and severe disease.[29] It is the most common ...
... increasing airway resistance. The bronchoconstriction is also caused by left ventricular dysfunction, caused by the SRTXs. Left ... it was found that there was a marked increase in airway resistance. This was likely caused by bronchoconstriction. ... "Resistance of the egyptian mongoose to sarafotoxins". Toxicon. 35 (8): 1251-1261. doi:10.1016/s0041-0101(97)00019-6. Lüscher, ... Bronchoconstriction occurred due to constriction of smooth muscle and airway wall thickening due to peribronchial edema. This ...
... of the total resistance originating at the nasal passages. Decreased resistance reduces the airway forces across the pulmonary ... In the case where no blood is visible in the trachea, EIPH in the small airways may still be present and can be confirmed by a ... Ramzan, Peter H.L. (2014). "Respiratory conditions: lower airway disease". The racehorse: a veterinary manual. pp. 222-234. ... Bronchoalveolar lavage (BAL) is a procedure whereby a small volume of fluid is put into the airways in order sample the cells ...
Upper Airway Resistance Syndrome, or Obstructive Sleep Apnea Syndrome". The Laryngoscope. 107 (6): 726-734 "Clinical Program - ... Upper Airway Resistance Syndrome, or Obstructive Sleep Apnea Syndrome". The Laryngoscope. 107 (6): 726-734. doi:10.1097/ ... "Recognition and Surgical Management of the Upper Airway Resistance Syndrome". The Laryngoscope. 106 (9): 1089-1093 Terris, D. J ... "Recognition and Surgical Management of the Upper Airway Resistance Syndrome". The Laryngoscope. 106 (9): 1089-1093. doi:10.1097 ...
Airway resistance is typically increased by bronchospasm and airway secretions. Chest wall compliance can be decreased by fixed ... which eliminates the effects of airway resistance. Pplat is never > PIP and is typically < 3-5 cmH2O lower than PIP when airway ... Alterations in airway resistance, lung compliance and chest wall compliance influence Cdyn. C s t a t = V T P p l a t − P E E P ... Lung compliance Chest wall compliance Airway resistance Lung compliance is influenced by a variety of primary abnormalities of ...
Partitioning airway and lung tissue resistances in humans: effects of bronchoconstriction. J Appl Physiol 82: 1531-1541, 1997. ... Airway caliber in healthy and asthmatic subjects: effects of bronchial challenge and deep inspirations. J Appl Physiol 91: 506- ... Tissue resistance and the contractile state of lung parenchyma. J Appl Physiol 74: 1387-1397, 1993. Fredberg JJ, Jones KA, ... Friction in airway smooth muscle: mechanism, latch, and implications in asthma. J Appl Physiol 81: 2703-2712, 1996. Bursac P, ...
Suction airway secretions with variable airway resistance. *Palpable pulse. *Responds to needle thoracentesis and chest tube ... Airway trauma features: upper airway obstruction, laryngospasm and bronchial occlusion for intubation ... Responds to airway trauma or obstruction: esophageal, nasal and oral intubation, and BVM ventilation and laryngoscopic ...
The Inspire Upper Airway Stimulation system senses respiration and applies mild electrical stimulation during inspiration, ... continuous positive airway pressure improves insulin resistance in patients with sleep apnea without diabetes". Annals of the ... or automatic positive airway pressure (APAP) device.[46][47] These splint the person's airway open during sleep by means of ... "Inspire Upper Airway Stimulation - P130008". FDA.gov. Food and Drug Administration. 11 January 2016. Archived from the original ...
The increased airway resistance that is associated with obstructive sleep apnea may also lead to nocturnal polyuria. ...
... lung volumes and airway resistance in normal children ages 5 to 18". Br J Dis Chest. 64 (1): 15-24. doi:10.1016/S0007-0971(70) ... It measures the airflow through the bronchi and thus the degree of obstruction in the airways. Peak flow readings are higher ... The Airways Journal. 2 (2): 80. Retrieved 2006-06-06. Nunn A, Gregg I (1989). "New regression equations for predicting peak ... when patients are well, and lower when the airways are constricted. From changes in recorded values, patients and doctors may ...
Unilateral measurements are performed to detect any asymmetry or abnormality in nasal airway resistance. When the measurements ... Increased resistance on rhinomanometry after allergen application is an objective mean in proving allergy to airborne allergens ... Nasal obstruction leads to increased values of nasal resistance. Rhinomanometry may be used to measure only one nostril at a ... Increased pressure during respiration is a result of increased resistance to airflow through nasal passages (nasal blockage), ...
"Enlargement of the lateral pharyngeal fat pad space in pigs increases upper airway resistance". Journal of Applied Physiology. ...
... decreasing resistance in the respiratory airway and increasing airflow to the lungs. Bronchodilators may be endogenous ( ... From among 6000 compounds that relax the smooth muscle cells of the lungs' airways and open up the airways in asthmatic lung ... agonist that relaxes airway smooth muscle cells and reduces asthmatic pulmonary resistance. The authors claim that "TSG12 is ... These medications may take longer to begin working, but relieve airway constriction for up to 12 hours. Commonly taken twice a ...
This narrows the upper airway during sleep, increasing resistance and making airflow through the upper airway turbulent and ... The upper airway becomes more floppy.. *The rhythmic innervation results in weaker muscle contractions because the ... This problem is exacerbated in overweight people when sleeping on the back, as extra fat tissue may weigh down on the airway, ... During non-REM sleep, the tonic drive to most respiratory muscles of the upper airway is inhibited. This has two consequences: ...
The increased fluid in the lungs leads to increased airway resistance and reduced lung compliance. It is thought this could be ...
With only a thoracic signal, all parameters can be obtained except for specific airway resistance (SRaw) and specific airway ... Another important parameter, which can be calculated with a body plethysmograph is the airway resistance. During inhalation the ... While observing the so-called resistance loop (cabin pressure and flow), diseases can easily be recognized. If the resistance ... including airway resistance and conductance. Different sizes of plethysmograph exist to study mice, rats or guinea pigs. The ...
Pplat is never bigger than PIP and is typically < 3-5 cm H2O lower than PIP when airway resistance is not elevated. PEEP is ... During this maneuver, airflow is transiently (~0.5 sec) discontinued, which eliminates the effects of airway resistance. ... Alterations in airway resistance, lung compliance and chest wall compliance influence Cdyn. Lung compliance is an important ...
A 2013 review found an instant increase in airway resistance after using a single e-cigarette. Any reported harmful effects to ... The short-term toxicity of e-cigarette use appears to be low, with the exception for some people with reactive airways. The ... A 2015 PHE report concluded that the risks of fire from e-cigarettes "appear to be comparable to similar electrical goods". ... A 2014 review found "disposable e-cigarettes might cause an electrical waste problem." Since the majority of e-cigarettes are ...
Increased airways resistance (chronic obstructive pulmonary disease, asthma, suffocation). *Reduced breathing effort (drug ... continuous positive airway pressure can be useful when started before conveying to hospital.[3] ... "Continuous positive airway pressure and noninvasive ventilation in prehospital treatment of patients with acute respiratory ...
FEV1 is diminished because of increased airway resistance to expiratory flow; the FVC may be decreased as well, due to the ... but the former is more affected because of the increased airway resistance). This generates a reduced value (,80%, often ~45 ... It is sometimes directly followed by a rapid inhalation (inspiration), in particular when assessing possible upper airway ... Actual volume of the lung including the volume of the conducting airway. ...
Laminar flow tends to generate less resistance than turbulent flow. In the small airways where flow is laminar, resistance is ... The Hagen-Poiseuille equation describes laminar resistance. In the large airways where flow is turbulent, resistance is ... The mixture generates less resistance than atmospheric air when passing through the airways of the lungs, and thus requires ... Currently, heliox is mainly used in conditions of large airway narrowing (upper airway obstruction from tumors or foreign ...
Drug resistance is increasingly more common and presents a serious problem in persons who are immunocompromised. Prophylactic ... CS1 maint: Extra text: authors list (link) Inhaled steroids in asthma optimizing effects in the airways. [S.l.]: Marcel Dekker ...
The buildup of fat leads to a decrease in chest well compliance and increase in airway resistance, both of which are ...
... of total airway resistance.{ref6} The nasal cavity has been modeled as 2 resistors in parallel.{ref1}{ref9} The 3 components of ... Nasal airway resistance accounts for more than 50% of total airway resistance. [6] The nasal cavity has been modeled as 2 ... Its overall contribution to total airway resistance is small. The component of nasal cavum resistance is determined by degree ... Nasal resistance increases markedly in the first 2-3 cm of the nasal airway. [1] ...
The effect of rapid maxillary expansion on nasal airway resistance.. Hartgerink DV1, Vig PS, Abbott DW. ... Nasal resistance measurements, assessed in four modes (natural state, anterior nares dilation with Tygon tubing, following ... Individual variation in nasal resistance values was considerable and hence the median response for the group was not a reliable ... The purpose of this study was to evaluate changes in nasal resistance to airflow in persons undergoing rapid maxillary ...
Apparently, according to the paper work I have a diagnosis of upper airway resistance syndrome (23 arousals an hour). No one ... Treatment for Upper Airway Resistance Syndrome nipsic987 Hello, I just reviewed my medical records which included a sleep study ... Apparently, according to the paper work I have a diagnosis of upper airway resistance syndrome (23 arousals an hour). No one ... Create an account to receive updates on: Treatment for Upper Airway Resistance Syndrome ...
... eUAR stands for Expiratory Upper Airway Resistance. eUAR is defined as Expiratory Upper Airway Resistance very rarely. ... www.acronymfinder.com/Expiratory-Upper-Airway-Resistance-(eUAR).html. *Chicago style: Acronym Finder. S.v. "eUAR." Retrieved ... www.acronymfinder.com/Expiratory-Upper-Airway-Resistance-(eUAR).html,eUAR,/a,. ... www.acronymfinder.com/Expiratory-Upper-Airway-Resistance-(eUAR).html ...
... airway resistance is the resistance of the respiratory tract to airflow during inhalation and expiration. Airway resistance can ... these airways may collapse causing increased airway resistance. This is simply the mathematical inverse of airway resistance. G ... in asthma during an attack the airways constrict causing an increase in airway resistance. Airway resistance can also vary ... An individual small airway has much greater resistance than a large airway, however there are many more small airways than ...
Upper airway resistance syndrome or UARS is a common sleep disorder characterized by the narrowing of the airway that can cause ... Upper airway resistance syndrome is caused when the upper airway narrows without closing. Consequently, airflow is either ... "Upper airway resistance syndrome in children". Seminars in Pediatric Neurology: 207-215 - via Elsevier. "Upper Airway ... Medicine portal Airway resistance Sleep apnea Shneerson, John M., ed. (2005). Sleep Medicine (Second ed.). New York: Blackwell ...
... surgical intervention did not change structural shape or resistance during normal breathing; however, researchers found ... Rhinoplasty has little effect on airway, resistance for external nasal valve dysfunction. Source/Disclosures Source: Palesy T, ... According to the researchers, a relationship between nasal airway resistance and minimum cross-sectional area may exist, where ... However, no significant changes were observed for median nasal airway resistance or the minimum cross-sectional area. ...
Monitoring of airway resistance (Raw) in exacerbation of asthma Message Subject (Your Name) has sent you a message from ... Monitoring of airway resistance (Raw) in exacerbation of asthma. Tajana Jalusic Gluncic, Latinka Basara Toromanovic ...
Browse by Outcome: Airway Resistance (2 articles). % of records by year: 1965 2017 ...
AIRWAY RESISTANCE You will receive an email whenever this article is corrected, updated, or cited in the literature. You can ... J. A. Nadel, J. G. Widdicombe; AIRWAY RESISTANCE. Anesthesiology 1963;24(2):266. ... Effects of Changes in Blood Gas Tension and Carotid Sinus Pressure on Airway calibre of Dogs.) ...
AIRWAY RESISTANCE You will receive an email whenever this article is corrected, updated, or cited in the literature. You can ...
Cartilaginous airway wall dimensions and airway resistance in cystic fibrosis lungs. HA Tiddens, LP Koopman, RK Lambert, WM ... Cartilaginous airway wall dimensions and airway resistance in cystic fibrosis lungs. HA Tiddens, LP Koopman, RK Lambert, WM ... Cartilaginous airway wall dimensions and airway resistance in cystic fibrosis lungs. HA Tiddens, LP Koopman, RK Lambert, WM ... Cartilaginous airway wall dimensions and airway resistance in cystic fibrosis lungs Message Subject (Your Name) has sent you a ...
1. The inverse relationship between airway resistance and lung volume contributes to variation in measurement of resistance, as ... of airway resistance was compared with conventional volume-standardized variables such as specific airway resistance, specific ... A Method for Standardizing Airway Resistance for Variations in Lung Volume. T. Higenbottam, T. J. H. Clark ... A Method for Standardizing Airway Resistance for Variations in Lung Volume Message Subject (Your Name) has forwarded a page to ...
... airway caliber, lung volumes and their combination, specific resistance) and that resistance parameters of the two techniques ... while Rrsmean and Raw0.5 explored more central airways. Only specific resistances taking into account the specific resistance ... resistance extrapolated at 0 Hz [Rrs0 Hz], mean resistance [Rrsmean], and resistance/frequency slope [Rrsslope]) and (2) to ... to compare numerical parameters of specific airway resistance (total, sRawtot, effective, sRaweff and at 0.5 L • s-1, sRaw0.5) ...
But airways resistance continues to increase and could be a more sensitive measurement of further airways disease. ... Peripheral Airways Resistance, Static Recoil and the Forced Expiratory Volume Ruth M. Cayton Ruth M. Cayton ... Ruth M. Cayton, P. Howard; Peripheral Airways Resistance, Static Recoil and the Forced Expiratory Volume. Clin Sci 1 April 1972 ... and at this stage is considered a sensitive indicator of peripheral airways resistance. In stage 3 the FEV is low and further ...
5.3 Airway Resistance - Shock Losses for Bends and Area Changes - Free download as PDF File (.pdf), Text File (.txt) or read ... not exist in physical form in the airways at all. Hence, we can say that the airway. first contract from Aa to Ao and then ... saveSave 5.3 Airway Resistance - Shock Losses for Bends and... For Later. ... saveSave 5.3 Airway Resistance - Shock Losses for Bends and... For Later. ...
Glucocorticosteroid effects on cytokine production: studies in a glucocorticosteroid resistance model and in allergic airway ... produced during allergic airway inflammation have been proposed to induce the resistance to GCS. IL-2 and IL-4 also induce GCS ... produced during allergic airway inflammation have been proposed to induce the resistance to GCS. IL-2 and IL-4 also induce GCS ... produced during allergic airway inflammation have been proposed to induce the resistance to GCS. IL-2 and IL-4 also induce GCS ...
Influence on airway resistance and functional residual capacity. Together they form a unique fingerprint. * Sort by ...
We assessed associations of long-term air pollution exposure with airway resistance. Methods: We measured airway resistance at ... Air pollution and airway resistance at age 8 years - The PIAMA birth cohort study. Publication. Publication. Environmental ... Air pollution and airway resistance at age 8 years - The PIAMA birth cohort study. Environmental Health: A Global Access ... but measurements of airway resistance may provide additional information. ...
... upper airway resistance syndrome (UARS), and obstructive sleep apnea (OSA) ... Sleep disordered breathing can be severe to the point of complete airway collapse where your airway gets sucked closed.. Those ... These appliances allow maximum airway capacity. It gently holds your jaw in the correct position to maintain proper airway flow ... upper airway resistance syndrome (UARS), and obstructive sleep apnea (OSA).. Obstructive Sleep Apnea (OSA) is defined by the ...
Multiday Exposure of Men to High Nitrogen Pressure and Increased Airway Resistance at Natural Expired Oxygen Tension: A 14-day ... Multiday Exposure of Men to High Nitrogen Pressure and Increased Airway Resistance at Natural Expired Oxygen Tension: A 14-day ... Multiday Exposure of Men to High Nitrogen Pressure and Increased Airway Resistance at Natural Expired Oxygen Tension: A 14-day ...
"Sciatic Nerve Stimulation and its Effects on Upper Airway Resistance in the Anesthetized Rabbit Model Relevant to Sleep Apnea, ... upper airway resistance was unchanged. Hypoglossal stimulation reduced resistance without altering drive. While sciatic nerve ... upper airway resistance was unchanged. Hypoglossal stimulation reduced resistance without altering drive. While sciatic nerve ... Sciatic Nerve Stimulation and its Effects on Upper Airway Resistance in the Anesthetized Rabbit Model Relevant to Sleep Apnea. ...
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... aeruginosa Exploits Multiple Genetic Pathways To Develop Multidrug Resistance during Long-Term Infections in the Airways of ... Antimicrobial resistance in P. aeruginosa isolates recovered from cystic fibrosis (CF) patients is further enhanced by the ... Antibiotic resistance increased as infection progressed toward the establishment of a population constituted by genotypically ... aeruginosa Exploits Multiple Genetic Pathways To Develop Multidrug Resistance during Long-Term Infections in the Airways of ...
UARSApneaSpecific airwayNasal airway resistanceRespiratoryObstructing the upper airwayLungDeterminants of airway resistanceCPAPSpirometryHuman AirwayLaryngeal airway resistanceLower airwayDiameter of the airwayMeasure airway resistancePressuresInspiratorySmall airwaysIncrease in airwayPulmonaryEffect on airwayMeasurement of airwayCOPDCollapseMeasurementsArousalsTracheaPatientsContinuousPressure2018Long-term air pollution exposureInversely proportionalPeripheralHyperresponsivenessPatencyAirflow resistanceOccursInverseBreathingBronchodilatorDiseaseSmooth muscleNeomycin resistance cassetteReduction in nasal resistance
- Upper airway resistance syndrome or UARS is a common sleep disorder characterized by the narrowing of the airway that can cause disruptions to sleep. (wikipedia.org)
- It is unclear as to whether UARS is merely a phase that occurs between simple snoring and sleep apneas, or whether UARS is a syndrome that describes a deviation from normal upper airway physiology. (wikipedia.org)
- Those who suffer from sleep disordered breathing experience breathing difficulty ranging from mild to acute: snoring, upper airway resistance syndrome (UARS), and obstructive sleep apnea (OSA). (dental--health.com)
- Over the past 10 years, our ability to recognize, treat, and identify the morbidity associated with the upper airway resistance syndrome (UARS) has improved vastly. (semanticscholar.org)
- Upper Airway Resistance Syndrome (UARS) is a common and under-diagnosed condition that can affect any age group. (lucohybridosa.com)
- UARS does not result in the characteristic apnea events or cessation of breathing seen in OSA, but rather the sleep deprivation caused by frequent arousals due to recurrent collapsing of the trachea (airway). (lucohybridosa.com)
- In contrast, UARS has an intact neurological system and the ability to respond to even minor changes in the upper airway dimension and resistance airflow. (lucohybridosa.com)
- The reason UARS is found more often in young, fit females is that smaller frames means narrower airways which makes them more prone to obstructions from structures such as the adenoids, tonsils, tongue and uvula. (thedentalstation.com.au)
- As in sleep apnoea, the soft tissue of the airway in UARS patients relaxes while one sleeps. (thedentalstation.com.au)
- Upper Airway Resistance Syndrome or UARS is a sleep condition characterized by airway resistance to breathing during sleep. (healthysleeptexas.com)
- Typically, the airway of a UARS patient is already restricted or reduced in size, and this natural relaxation reduces the airway further. (healthysleeptexas.com)
- Pathophysiology of UARS is similar to obstructive sleep apnea / hypopnea syndrome in that abnormal airway resistance in the upper airway during sleep leads to unwanted physiologic consequences. (healthysleeptexas.com)
- At Sleep & Neuroscience Associates, the leading sleep center in Greenwich, CT , we provide diagnosis and treatment for a wide range of sleep disorders, including obstructive sleep apnea ( OSA ) and upper airway resistance syndrome ( UARS ) treatment. (sleepwellmd.com)
- Learn more about our sleep apnea and upper airway resistance syndrome (UARS) treatment options below, or schedule an appointment with our sleep apnea doctors and specialists to sleep better and live better today. (sleepwellmd.com)
- Upper airway resistance syndrome is a precursor to obstructive sleep apnea, and it is important to identify and treat patients with UARS since they have a higher risk of developing obstructive sleep apnea in the future. (sleepwellmd.com)
- Upper airway resistance syndrome, also known as UARS, occurs when your airways constrict, causing interruptions during sleep. (dental365sleep.com)
- What causes upper airway resistance syndrome (UARS)? (dental365sleep.com)
- When airways become blocked during sleep, your body needs to work harder to carry air to your lungs, causing sufferers of UARS to experience labored breathing during sleep. (dental365sleep.com)
- Because UARS and OSA share similar symptoms, your doctor will likely conduct a sleep study to help accurately diagnose upper airway resistance syndrome. (dental365sleep.com)
- Ruhle and colleagues suggested in a recent review that upper airway impedance measurements using the forced oscillation technique may be useful as a surrogate of Pes in the diagnosis of UARS. (advances-in-medicine.net)
- Given the currently available information, the most plausible explanation for daytime somnolence in UARS is that sleep disruption from multiple brief arousals occurs as a result of increasingly negative intrathoracic and airway pressure, with the response most likely mediated by mechanoreceptors in the upper airway. (advances-in-medicine.net)
- A less well-known, yet common Sleep Disorder, is Upper Airways Resistance Syndrome (UARS) and is often the case when people have a sleep study with too low an AHI (apnoea-hypopnoea index) score to be classed as a diagnosis for Sleep Apnoea. (hope2sleep.co.uk)
- If you find yourself dealing with insomnia, tossing and turning, or if you wake up exhausted then you could be dealing with upper airway resistance syndrome (UARS). (pacificsleepprogram.com)
- Those with UARS may have loose tissue in the back of the throat, which is prone to collapsing and blocking the airways while asleep. (pacificsleepprogram.com)
- Those with UARS will only experience a reduction in breathing due to airway constrictions. (pacificsleepprogram.com)
- Research has shown a link between hypothyroidism and a condition known as upper airway resistance syndrome, or UARS. (healthcentral.com)
- With UARS, airway resistance is significant enough to disrupt your sleep by causing insomnia, snoring, apnea, and unrefreshing sleep. (healthcentral.com)
- Hear from leading experts in the field of obstructive sleep apnea (OSA) and upper airway resistance syndrome (UARS) what you can do to overcome these chronic health problems. (doctorstevenpark.com)
- Conditions that may be linked to this problem are upper airway resistance syndrome (UARS) or even obstructive sleep apnea which both indicate a frightening lack of oxygen while you're sleeping. (verywellhealth.com)
- A lesser-known consequence of breathing complications during sleep is Upper Airway Resistance Syndrome (UARS for short). (verywellhealth.com)
- UARS is caused by narrowing of the upper airway may be described as trying to breathe through an opening as small as a straw. (verywellhealth.com)
- Positive airway pressure therapy is similar to that in obstructive sleep apnea and works by stenting the airway open with pressure, thus reducing the airway resistance. (wikipedia.org)
- Contact a Sleep Apnea specialist to obtain the diagnostic information you may need for determining if mask devices or airway orthotics can help. (dental--health.com)
- Strohl, Kingman Perkins 2018-03-13 00:00:00 Obstructive sleep apnea (OSA) is a disorder characterized by collapse of the velopharynx and/or oropharynx during sleep when drive to the upper airway is reduced. (deepdyve.com)
- Increased upper airway resistance in this disorder does not lead to cessation of airflow (apnea) or decrease in airflow (hypopnea), but instead leads to an arousal secondary to increased work of breathing to overcome the resistance. (healthysleeptexas.com)
- It is commonly believed that sleep apnea begins as subtle airway collapse which may or may not be associated with snoring. (sleepwellmd.com)
- Board-certified sleep specialist and sleep apnea doctor, Dr. Samit Malhotra analyzes patient symptoms and concerns to make a diagnosis of sleep apnea or upper airway resistance syndrome. (sleepwellmd.com)
- For patients in whom obstructive sleep apnea (OSA) is suspected or is diagnosed, examination of the upper airway is essential for determining an optimal treatment, as many variables are involved in the pathogenesis of the disease, making the choice of the correct treatment a complex one. (medscape.com)
- Upper airway resistance syndrome may progress to obstructive sleep apnea, which may lead to serious health-related issues, such as diabetes, heart disease, and stroke. (dental365sleep.com)
- Similar to obstructive sleep apnea , upper airway resistance is likely the result of airways becoming partially or fully blocked during sleep. (dental365sleep.com)
- Obstructive sleep apnea is a condition in which individuals experience pauses in breathing (apnea) during sleep, which are associated with partial or complete closure of the throat (pper airway). (medlineplus.gov)
- Upper airway resistance during sleep can present with a range of symptoms from simple snoring (SS) through to severe obstructive sleep apnea (OSA). (clinicaltrials.gov)
- A San Diego dental device treatment center for obstructive sleep apnea, snoring and upper airway resistance syndrome. (abclinicsd.com)
- It is not practically possible to measure airway resistance at a set absolute lung volume, therefore specific airway resistance attempts to correct for differences in lung volume at which different measurements of airway resistance were made. (wikipedia.org)
- Similarly to specific airway resistance, specific airway conductance attempts to correct for differences in lung volume. (wikipedia.org)
- The corrected measurement of airway resistance was compared with conventional volume-standardized variables such as specific airway resistance, specific airway conductance and the logarithmic transformation of the latter. (clinsci.org)
- Specific airway resistance (sR aw ), or its reciprocal specific airway conductance (sG aw ), was first introduced over 35 years ago as a way to gather information on airflow resistance in conscious subjects during quiet spontaneous breathing. (scireq.com)
- Background: Airway resistance (R AW ) and specific airway conductance (sG AW ) are measures that reflect the patency of airways. (unamur.be)
- Nasal airway resistance accounts for more than 50% of total airway resistance. (medscape.com)
- [ 11 ] Going from a supine to an upright position decreases jugulovenous distention and nasal airway resistance. (medscape.com)
- The voluntary flaring of the naris has been attributed to a possible 20% reduction of nasal resistance, a product of facial nerve contribution to nasal airway resistance. (medscape.com)
- The effect of rapid maxillary expansion on nasal airway resistance. (nih.gov)
- However, no significant changes were observed for median nasal airway resistance or the minimum cross-sectional area. (healio.com)
- According to the researchers, a relationship between nasal airway resistance and minimum cross-sectional area may exist, where the shape of the minimum cross-sectional area may be just as important as the minimum cross-sectional area value because the shape has consequences for both airflow and nasal airway resistance. (healio.com)
- In respiratory physiology, airway resistance is the resistance of the respiratory tract to airflow during inhalation and expiration. (wikipedia.org)
- As shown above airway resistance is markedly affected by changes in the diameter of the airways, therefore diseases affecting the respiratory tract can increase airway resistance. (wikipedia.org)
- 3. It is suggested that the use of the FEV as a test of respiratory function during the natural history of obstructive airways disease should be considered in three stages. (portlandpress.com)
- Our primary hypothesis is that desflurane at high concentrations will cause an increase of respiratory resistance partially due to increased density of the inspired gas mixture. (isrctn.com)
- The purpose of this study was to determine whether pharmacologic interventions which increase respiratory drive could also reduce flow resistance in the upper airway. (semanticscholar.org)
- Some have an increase in respiratory effort only due to anatomical restrictions in the upper airway such as deviated septums, large turbinates, or congenitally narrow nasal passages. (lucohybridosa.com)
- While the assumptions of the Hagen-Poiseuille equation are not strictly true of the respiratory tract it serves to show that, because of the fourth power, relatively small changes in the radius of the airways causes large changes in airway resistance. (fxsolver.com)
- Limitations of these approaches preclude assessment of the influence of mechanical properties of the musculoskeletal system and motivated development of a biomechanical model of the respiratory muscles, airway, and lungs using published measures from human subjects. (frontiersin.org)
- Here we describe the model and some aspects of its behavior when linked to a computational brainstem respiratory network model for breathing and airway defensive behavior composed of discrete "integrate and fire" populations. (frontiersin.org)
- In addition to information on flow, information on the alveolar pressure changes is typically needed to characterise resistance to airflow within the respiratory system. (scireq.com)
- Respiratory sound analysis is a simple and noninvasive way to study the pathophysiology of the upper airway (UA). (bresotec.com)
- 2-adrenoceptor agonists and therapy of respiratory airway disorders SABAs are generally used as save bronchodilator therapy to supply symptomatic alleviation for individuals with exacerbations of asthma or COPD. (elevateblogconference.com)
- Objective To compare the effect of heated, humidified, high-flow nasal cannula (HHHFNC) and nasal continuous positive airways pressure (NCPAP) on lung function and mechanics in preterm infants with respiratory distress syndrome (RDS) at the same level of retropharyngeal pressure (P rp ). (bmj.com)
- Compared to nasal continuous positive airway pressure (NCPAP), heated humidified high flow nasal cannula (HHHFNC) offers ease of use, better tolerance and improved feeding and bonding in preterm newborns requiring non-invasive respiratory support. (bmj.com)
- If the bruxism is severe, the patient will lose height in their teeth increasing their overbite while retruding the mandible (further obstructing the upper airway). (lucohybridosa.com)
- Due to the elastic nature of the tissue that supports the small airways airway resistance changes with lung volume. (wikipedia.org)
- Airway dimensions were measured in lungs obtained from CF patients who had undergone lung transplantation (n=12), lobectomy (n=1), or autopsy (n=4). (ersjournals.com)
- 1. The inverse relationship between airway resistance and lung volume contributes to variation in measurement of resistance, as it is difficult to control precisely the lung volume at which resistance is determined each time. (clinsci.org)
- A correction for variation in lung volume was applied to measurement of airway resistance by using analysis of covariance with lung volume as a covariate. (clinsci.org)
- This method provides an assessment in each subject of degree of association between airway resistance and lung volume and uses the individual's unique slope, relating resistance to volume in order to correct resistance to a single lung volume. (clinsci.org)
- 2. Eight normal male subjects had airway resistance and lung volume measured in a body plethysmograph, a mean of seven measurements being made. (clinsci.org)
- 3. Airway resistance showed only a limited association with lung volume and the slopes relating the two measurements varied between subjects. (clinsci.org)
- 4. Analysis of covariance adequately corrects airway resistance for variations in lung volume but further studies are required to validate its precision and sensitivity. (clinsci.org)
- In forced expiration the lung compresses and the small airways are narrowed, causing the resistance to increase further. (teachmephysiology.com)
- Airway resistance (RL) and dynamic compliance (Cdyn) as measures of lung function and airway reactivity. (nih.gov)
- Its units are cmH 2 O.s while typical airway resistance units would be cmH 2 O.s/mL. sR aw rather denotes work of breathing as it is defined by the product of airway resistance and the lung volume at the end of inspiration, the functional residual capacity or FRC. (scireq.com)
- The flexiVent system offers detailed lung function measurements which can prove helpful in identifying the response site within the lower airway segment while also providing direct upper airway resistance measurements. (scireq.com)
- The majority of these pathologic features of human airway inflammation have also been observed in experimental lung injury models. (jimmunol.org)
- Systemic LPS administration induces neutrophil sequestration into the pulmonary microvasculature without passage into the lung tissues and bronchoalveolar space ( 12 ), whereas neutrophil recruitment upon aerogenic LPS exposure occurs in all airway compartments ( 8 ). (jimmunol.org)
- However, pulmonary resistance (R(L)) is the sum of airway resistance (R(aw)), which changes with airway caliber, and of tissue resistance (R(ti)), which depends on the pressure-volume hysteresis of the lung. (elsevier.com)
- The authors conclude that changes in R(L) during halothane administration are caused not only by changes in airway caliber, as previously assumed, but also reflect a significant effect of halothane on lung tissue pressure-volume hysteresis. (elsevier.com)
- To learn about your lung health, your doctor may want you to have several pulmonary function tests done including spirometry , lung volumes , diffusing capacity , and airway resistance. (getasthmahelp.org)
- There are several important determinants of airway resistance including: The diameter of the airways Whether airflow is laminar or turbulent In fluid dynamics, the Hagen-Poiseuille equation is a physical law that gives the pressure drop in a fluid flowing through a long cylindrical pipe. (wikipedia.org)
- Reimbursement for the positive airway pressure device (CPAP etc.) may be a concern in certain healthcare models. (healthysleeptexas.com)
- Based on the results, your sleep specialist may recommend a variety of treatments, including a CPAP (continuous positive airway pressure) device, oral devices that help keep the airway open and prevent snoring, specialized upper airway stimulation (UAS) therapy, or surgery. (healthcentral.com)
- Forced expiratory volume in 1 s and forced vital capacity from spirometry have been studied most frequently, but measurements of airway resistance may provide additional information. (eur.nl)
- Using human airway epithelial cells as a proper in vitro model, we show that prior exposure to physiological nanomolar serum concentrations of simvastatin (ranging from 10-1,000 nM) confers significant cellular resistance to the cytotoxicity of pneumolysin, a pore-forming toxin and the main virulence factor of Streptococcus pneumoniae. (ewha.ac.kr)
- OBJECTIVE To evaluate the effect of bilateral ventriculocordectomy via ventral laryngotomy on laryngeal airway resistance (LAR) in canine cadaver larynges. (avmi.net)
- Direct measures of subglottal pressure obtained through a tracheal puncture were used to calculate laryngeal airway resistance. (naver.com)
- Laryngeal airway resistance of older men and women as a function of vocal sound pressure level. (naver.com)
- Laryngeal airway resistance during vowel production in adult females. (naver.com)
- [ 1 ] The lower airway begins in the trachea and continues to the bronchial tree. (medscape.com)
- Since both factors can influence the outcome of sR aw and that there is an inverse relationship between them, best practice would be to complement measurements of sR aw with direct measurements of both upper and lower airway resistance. (scireq.com)
- The level of resistance depends on many things, particularly the diameter of the airway and whether flow is laminar or turbulent. (teachmephysiology.com)
- Poiseuilles Law , also known as the Hagen-Poiseuille equation, gives us the relationship between airway resistance and the diameter of the airway. (teachmephysiology.com)
- The relaxation of these muscles in turn reduces the diameter of the airway. (healthysleeptexas.com)
- Pulmonary function tests and body plethysmography to measure airway resistance were performed to the subjects. (cdc.gov)
- 1. The forced expiratory volume (FEV 0·75 ) was measured at increasing mouth pressures in twenty-seven patients with obstructive airways disease. (portlandpress.com)
- Subsequently, the inhaled agent will be turned off and two further measurements of flow and airway pressures will be recorded, when end tidal concentrations reach 0.5 and 0 MAC. (isrctn.com)
- An individual small airway has much greater resistance than a large airway, however there are many more small airways than large ones. (wikipedia.org)
- On inspiration , the positive pressure within the alveoli and small airways causes the diameter to increase, and therefore resistance to decrease. (teachmephysiology.com)
- Increase in airway resistance in COPD occurs due to a loss or narrowing of small airways, which precedes the development of emphysema. (medindia.net)
- These dimensions were compared to those of airways from lobectomy specimens from 72 patients with various degrees of chronic obstructive pulmonary disease (COPD). (ersjournals.com)
- In mice, aerogenic exposure to endotoxin or LPS, a major component of the outmost membrane of Gram-negative bacteria, induces pulmonary inflammation with recruitment and activation of macrophages and neutrophils in the airways, local TNF production, alveolar-capillary leak, and also a direct bronchoconstriction ( 8 ). (jimmunol.org)
- Alteration of pulmonary chemokine expression in c-Rel-deficient mice may inhibit allergen-induced pulmonary inflammation and airway hyperresponsiveness. (jimmunol.org)
- We have previously shown the importance of T lymphocyte costimulation and activation in a murine model of allergen-induced pulmonary inflammation and airway hyperresponsiveness (AHR) 3 ( 1 , 2 , 3 , 4 ). (jimmunol.org)
- Studies of the effect of halothane on airway smooth muscle have used pulmonary resistance as an index of airway caliber. (elsevier.com)
- Associations between TGF-β1 G/A and TNF-α 308 G/A gene polymorphisms with airway resistance in chronic obstructive pulmonary disease]. (cdc.gov)
- The airway dimensions of the CF and COPD patients were introduced into a computational model to study their effect on airway resistance. (ersjournals.com)
- While sR aw captures information on airflow resistance, it is important to realize that it is not a true measurement of airway resistance. (scireq.com)
- The inner wall and smooth muscle areas of peripheral CF airways were increased 3.3- and 4.3-fold respectively compared to those of COPD airways. (ersjournals.com)
- The sensitivity and maximal plateau resistance of the computed dose/response curves were substantially increased in the CF patients compared to COPD patients. (ersjournals.com)
- The aim of the present study was to evaluate the associations between airway resistance with TGF-β1 G/A and TNF-α 308 G/A gene polymorphisms in COPD patients. (cdc.gov)
- These results can suggest the lack of association between TNF-α 308 G/A and TGF-β1 800 G/A gene polymorphisms with COPD development and airway resistance in Turkish population. (cdc.gov)
- Studies have shown 30 L/min is the limiting flow during inspiration at which nasal airway collapse occurs in this area. (medscape.com)
- Sleep disordered breathing can be severe to the point of complete airway collapse where your airway gets sucked closed. (dental--health.com)
- If the wind pipe is narrow, it can collapse blocking the airway. (lucohybridosa.com)
- Nasal resistance measurements, assessed in four modes (natural state, anterior nares dilation with Tygon tubing, following administration of decongestant, and nares dilation with tubing and decongestant), were taken on a group of 38 patients receiving rapid maxillary expansion and compared with a control group not receiving expansion. (nih.gov)
- Moreover, since air flow limitations are partly caused by increased airway resistance, direct measurements of airway resistance may provide additional information [ 10 ]. (biomedcentral.com)
- Apparently, according to the paper work I have a diagnosis of upper airway resistance syndrome (23 arousals an hour). (medhelp.org)
- If the patient gains weight or even just ages, this snoring (or upper airway resistance) leads to increased resistance and what is termed "snore arousals", where the patient's snoring wakes them from sleep. (lucohybridosa.com)
- Therefore, smaller airways such as bronchioles and alveolar ducts all individually have much higher flow resistance than larger airways like the trachea. (teachmephysiology.com)
- The aim of this study was to measure the airway dimensions of CF patients and to estimate the importance of these dimensions to airway resistance using a computational model. (ersjournals.com)
- Antimicrobial resistance in P. aeruginosa isolates recovered from cystic fibrosis (CF) patients is further enhanced by the occurrence of hypermutator strains, a hallmark of chronic infections in CF patients. (asm.org)
- We assess your posture, because many patients with obstructed airways posture their heads forward to help open the airway. (thedentalstation.com.au)
- Nasal continuous positive airway pressure for nonapneic snoring? (semanticscholar.org)
- Despite differing working mechanisms, both nasal continuous positive airway pressure (NCPAP) and HHHFNC provide a continuous positive airway pressure. (bmj.com)
- If flow becomes turbulent, and the pressure difference is increased to maintain flow, this response itself increases resistance. (wikipedia.org)
- Effects of Changes in Blood Gas Tension and Carotid Sinus Pressure on Airway calibre of Dogs. (asahq.org)
- there was no evidence from the (FEV/mouth pressure) plots that their airways functioned differently during forced expiration. (portlandpress.com)
- We have already learnt that obstructions, area changes, bends, etc. also contribute loss in pressure of air flowing through mine airways besides shape and size of mine airways and their corresponding roughness. (scribd.com)
- Ohms law can be used to describe the relationship between airflow, pressure gradient and resistance. (teachmephysiology.com)
- This demonstrates that as resistance increases, the pressure gradient must also increase to maintain the same airflow to the alveoli. (teachmephysiology.com)
- The opposite is true for expiration, airways narrow due to low pressure and so resistance is increased. (teachmephysiology.com)
- If airflow becomes turbulent, the pressure difference required to maintain airflow will need to be increased, which in turn would increase turbulence and therefore resistance. (teachmephysiology.com)
- Positive airway pressure therapy. (healthysleeptexas.com)
- Since upper airway resistance is a sleep disorder, it is likely that your doctor will recommend nocturnal esophageal manometry, an at-home test that can measure pressure changes within your thorax while you are sleeping. (dental365sleep.com)
- The RBF is directly proportional to the pressure gradient between the renal arteries and veins, and is inversely proportional to the resistance of the renal vessels. (hubpages.com)
- But blood flow remains constant, because the extent to which blood pressure rises or lowers, renal resistance has to increase or decrease proportionally. (hubpages.com)
- The increased renin concentration, increases the angiotensin II, which will cause an increase in resistance of the efferent arterioles and therefore increase glomerular hydrostatic pressure and thus regulating the glomerular filtration. (hubpages.com)
- Airway resistance (R aw ) is defined as the difference in pressure between the mouth and the alveoli (transrespiratory pressure) divided by the flow rate. (bartleby.com)
- This positive air pressure prevents the airway from closing during sleep. (prweb.com)
- Conclusions Despite differing mechanisms for generating positive airway pressure, when compared at the same P rp , NCPAP and HHHFNC provide similar effects on all the outcomes explored. (bmj.com)
- Even though the working mechanisms of HHHFNC are not yet fully understood, the washout of the upper airways (leading to a reduction of the physiological dead space) and the provision of a distending pressure are considered the most relevant. (bmj.com)
- Most Cited Content in 2018 from the Journal of Insulin Resistance . (insulinresistance.org)
- We assessed associations of long-term air pollution exposure with airway resistance. (eur.nl)
- Only four studies so far investigated associations between long-term air pollution exposure and airway resistance and only one of them has repeated measures of airway resistance to study changes in associations with age. (biomedcentral.com)
- With the present study, we add to the currently limited evidence regarding the association between long-term air pollution exposure and airway resistance with age. (biomedcentral.com)
- However, it shows that the airway resistance is inversely proportional to the radius to the power of 4. (teachmephysiology.com)
- The epithelium was 53% greater in height in peripheral CF airways. (ersjournals.com)
- There is an initial phase when peripheral airways disease develops with little or no alteration of the FEV. (portlandpress.com)
- In the second phase the FEV decreases from normal values to below 1·0 litre, and at this stage is considered a sensitive indicator of peripheral airways resistance. (portlandpress.com)
- c-Rel deficiency also prevented the induction of airway hyperresponsiveness. (jimmunol.org)
- If you suffer from sleep disordered breathing, as you fall asleep you experience a loss of muscle tone called airway patency . (dental--health.com)
- In the DCP technique, information on airflow resistance across the entire airway tree is extracted from the comparison of nasal and thoracic flow waveforms. (scireq.com)
- It is also used for airflow resistance in upper airway resistance syndrome. (medscape.com)
- [ 15 ] Active dilation of the dilator naris occurs during exercise, reducing airway resistance. (medscape.com)
- A major area of resistance occurs at the anterior tip of the inferior turbinate at the entrance to the piriform aperture. (medscape.com)
- This is simply the mathematical inverse of airway resistance. (wikipedia.org)
- Your response may help your doctor find out what kind and how much, if any, airway disease you may have, and whether you need medication to improve your breathing. (getasthmahelp.org)
- Normal breathing has a rounded pattern, while resistance to airflow leads to a squaring off of the flow signal. (medscape.com)
- This action widens the airway and reduces breathing resistance. (prweb.com)
- Often attributed to stress, new understanding of sleep and the airway reveal the reasons that people may grind their teeth could be the sign of nighttime breathing difficulty. (verywellhealth.com)
- It refers to the condition where increased resistance to breathing can lead to disruptions in sleep. (verywellhealth.com)
- A bronchodilator is an inhaled medication that may dilate, or open up, your airways. (getasthmahelp.org)
- But airways resistance continues to increase and could be a more sensitive measurement of further airways disease. (portlandpress.com)
- Charcot-Marie-Tooth disease has also been described in upper airway dysfunction. (medscape.com)
- Objectives: To determine whether maintenance of airway smooth muscle (ASM) shortening is responsible for the persistence of airway narrowing in healthy subjects following transient methacholine (MCh)-induced bronchoconstriction. (edu.au)
- A neomycin resistance cassette replaced the entire coding sequence and part of the 5' noncoding region. (jax.org)
- The four coding exons were replaced by a neomycin resistance cassette using the (129X1/SvJ x 129S1/Sv)F1- Kitl + -derived R1 embryonic stem (ES) cell line. (jax.org)
- Rebreathing has been shown to increase arterial carbon dioxide levels, causing nasal vasoconstriction and a reduction in nasal resistance. (medscape.com)
- There was a significant median reduction in nasal resistance following rapid maxillary expansion, measured in the natural state only, and this appeared to be stable up to 1 year after maximum expansion was obtained. (nih.gov)