Mountaineering: A sport involving mountain climbing techniques.Acclimatization: Adaptation to a new environment or to a change in the old.Tibet: An autonomous region located in central Asia, within China.Anoxia: Relatively complete absence of oxygen in one or more tissues.Atmospheric Pressure: The pressure at any point in an atmosphere due solely to the weight of the atmospheric gases above the point concerned.Atmosphere Exposure Chambers: Experimental devices used in inhalation studies in which a person or animal is either partially or completely immersed in a chemically controlled atmosphere.Athletic Performance: Carrying out of specific physical routines or procedures by one who is trained or skilled in physical activity. Performance is influenced by a combination of physiological, psychological, and socio-cultural factors.BoliviaNepalPulmonary 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.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.Adaptation, Physiological: The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT.Aircraft: A weight-carrying structure for navigation of the air that is supported either by its own buoyancy or by the dynamic action of the air against its surfaces. (Webster, 1973)Aerospace Medicine: That branch of medicine dealing with the studies and effects of flight through the atmosphere or in space upon the human body and with the prevention or cure of physiological or psychological malfunctions arising from these effects. (from NASA Thesaurus)Acetazolamide: One of the CARBONIC ANHYDRASE INHIBITORS that is sometimes effective against absence seizures. It is sometimes useful also as an adjunct in the treatment of tonic-clonic, myoclonic, and atonic seizures, particularly in women whose seizures occur or are exacerbated at specific times in the menstrual cycle. However, its usefulness is transient often because of rapid development of tolerance. Its antiepileptic effect may be due to its inhibitory effect on brain carbonic anhydrase, which leads to an increased transneuronal chloride gradient, increased chloride current, and increased inhibition. (From Smith and Reynard, Textbook of Pharmacology, 1991, p337)Decompression: Decompression external to the body, most often the slow lessening of external pressure on the whole body (especially in caisson workers, deep sea divers, and persons who ascend to great heights) to prevent DECOMPRESSION SICKNESS. It includes also sudden accidental decompression, but not surgical (local) decompression or decompression applied through body openings.Oxygen Consumption: The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)PeruRespiration: 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).Indians, South American: Individual members of South American ethnic groups with historic ancestral origins in Asia.Hemoglobins: The oxygen-carrying proteins of ERYTHROCYTES. They are found in all vertebrates and some invertebrates. The number of globin subunits in the hemoglobin quaternary structure differs between species. Structures range from monomeric to a variety of multimeric arrangements.Ranunculus: A plant genus of the family RANUNCULACEAE that contains protoanemonin, anemonin, and ranunculin.Skiing: A snow sport which uses skis to glide over the snow. It does not include water-skiing.Erythrocyte Volume: Volume of circulating ERYTHROCYTES . It is usually measured by RADIOISOTOPE DILUTION TECHNIQUE.Hypocapnia: Clinical manifestation consisting of a deficiency of carbon dioxide in arterial blood.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.Blood Gas Analysis: Measurement of oxygen and carbon dioxide in the blood.Carbonic Anhydrase Inhibitors: A class of compounds that reduces the secretion of H+ ions by the proximal kidney tubule through inhibition of CARBONIC ANHYDRASES.Wind: The motion of air relative to the earth's surface.Soccer: A game in which a round inflated ball is advanced by kicking or propelling with any part of the body except the hands or arms. The object of the game is to place the ball in opposite goals.Hematocrit: The volume of packed RED BLOOD CELLS in a blood specimen. The volume is measured by centrifugation in a tube with graduated markings, or with automated blood cell counters. It is an indicator of erythrocyte status in disease. For example, ANEMIA shows a low value; POLYCYTHEMIA, a high value.Radar: A system using beamed and reflected radio signals to and from an object in such a way that range, bearing, and other characteristics of the object may be determined.ColoradoRunning: An activity in which the body is propelled by moving the legs rapidly. Running is performed at a moderate to rapid pace and should be differentiated from JOGGING, which is performed at a much slower pace.Decompression Sickness: A condition occurring as a result of exposure to a rapid fall in ambient pressure. Gases, nitrogen in particular, come out of solution and form bubbles in body fluid and blood. These gas bubbles accumulate in joint spaces and the peripheral circulation impairing tissue oxygenation causing disorientation, severe pain, and potentially death.Lagomorpha: An order of small mammals comprising two families, Ochotonidae (pikas) and Leporidae (RABBITS and HARES). Head and body length ranges from about 125 mm to 750 mm. Hares and rabbits have a short tail, and the pikas lack a tail. Rabbits are born furless and with both eyes and ears closed. HARES are born fully haired with eyes and ears open. All are vegetarians. (From Nowak, Walker's Mammals of the World, 5th ed, p539-41)Polycythemia: An increase in the total red cell mass of the blood. (Dorland, 27th ed)Physical Endurance: The time span between the beginning of physical activity by an individual and the termination because of exhaustion.Flight, Animal: The use of wings or wing-like appendages to remain aloft and move through the air.Partial Pressure: The pressure that would be exerted by one component of a mixture of gases if it were present alone in a container. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Oximetry: The determination of oxygen-hemoglobin saturation of blood either by withdrawing a sample and passing it through a classical photoelectric oximeter or by electrodes attached to some translucent part of the body like finger, earlobe, or skin fold. It includes non-invasive oxygen monitoring by pulse oximetry.Carbon Dioxide: A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.Climate: The longterm manifestations of WEATHER. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Pulmonary Ventilation: The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.Geography: The science dealing with the earth and its life, especially the description of land, sea, and air and the distribution of plant and animal life, including humanity and human industries with reference to the mutual relations of these elements. (From Webster, 3d ed)Exercise: Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.Medicare Part A: The compulsory portion of Medicare that is known as the Hospital Insurance Program. All persons 65 years and older who are entitled to benefits under the Old Age, Survivors, Disability and Health Insurance Program or railroad retirement, persons under the age of 65 who have been eligible for disability for more than two years, and insured workers (and their dependents) requiring renal dialysis or kidney transplantation are automatically enrolled in Medicare Part A.Skating: Using ice skates, roller skates, or skateboards in racing or other competition or for recreation.Lepidium: A plant genus of the family BRASSICACEAE growing in Peru mountains. It is the source of maca root.Physical Exertion: Expenditure of energy during PHYSICAL ACTIVITY. Intensity of exertion may be measured by rate of OXYGEN CONSUMPTION; HEAT produced, or HEART RATE. Perceived exertion, a psychological measure of exertion, is included.Seasons: Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Bicycling: The use of a bicycle for transportation or recreation. It does not include the use of a bicycle in studying the body's response to physical exertion (BICYCLE ERGOMETRY TEST see EXERCISE TEST).Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Travel: Aspects of health and disease related to travel.AustriaCell Engineering: Methods and techniques used to modify or select cells and develop conditions for growing cells for biosynthetic production of molecules (METABOLIC ENGINEERING), for generation of tissue structures and organs in vitro (TISSUE ENGINEERING), or for other BIOENGINEERING research objectives.Pulmonary Circulation: The circulation of the BLOOD through the LUNGS.South AmericaHypertension, Pulmonary: Increased VASCULAR RESISTANCE in the PULMONARY CIRCULATION, usually secondary to HEART DISEASES or LUNG DISEASES.Meteorology: The science of studying the characteristics of the atmosphere such as its temperature, density, winds, clouds, precipitation, and other atmospheric phenomena and aiming to account for the weather in terms of external influences and the basic laws of physics. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Travel Medicine: Multidisciplinary field focusing on prevention of infectious diseases and patient safety during international TRAVEL. Key element of patient's pre-travel visit to the physician is a health risk assessment.Sports Medicine: The field of medicine concerned with physical fitness and the diagnosis and treatment of injuries sustained in exercise and sports activities.Abies: A plant genus in the family PINACEAE, order Pinales, class Pinopsida, division Coniferophyta. Balm of Gilead is a common name more often referring to POPULUS and sometimes to COMMIPHORA.Plasma Volume: Volume of PLASMA in the circulation. It is usually measured by INDICATOR DILUTION TECHNIQUES.Retinal Hemorrhage: Bleeding from the vessels of the retina.Ethiopia: An independent state in eastern Africa. Ethiopia is located in the Horn of Africa and is bordered on the north and northeast by Eritrea, on the east by Djibouti and Somalia, on the south by Kenya, and on the west and southwest by Sudan. Its capital is Addis Ababa.Ecosystem: A functional system which includes the organisms of a natural community together with their environment. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)Saxifragaceae: The saxifrage plant family of the order ROSALES, subclass Rosidae, class Magnoliopsida. The leaves are alternate and sometimes deeply lobed or form rosettes. The flowers have both male and female parts and 4 or 5 sepals and petals; they are usually in branched clusters. The fruit is a capsule with many seeds.Topography, Medical: The systematic surveying, mapping, charting, and description of specific geographical sites, with reference to the physical features that were presumed to influence health and disease. Medical topography should be differentiated from EPIDEMIOLOGY in that the former emphasizes geography whereas the latter emphasizes disease outbreaks.GeesePulmonary Gas Exchange: The exchange of OXYGEN and CARBON DIOXIDE between alveolar air and pulmonary capillary blood that occurs across the BLOOD-AIR BARRIER.Pulmonary Artery: The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs.Anaerobic Threshold: The oxygen consumption level above which aerobic energy production is supplemented by anaerobic mechanisms during exercise, resulting in a sustained increase in lactate concentration and metabolic acidosis. The anaerobic threshold is affected by factors that modify oxygen delivery to the tissues; it is low in patients with heart disease. Methods of measurement include direct measure of lactate concentration, direct measurement of bicarbonate concentration, and gas exchange measurements.Fascioliasis: Liver disease caused by infections with parasitic flukes of the genus FASCIOLA, such as FASCIOLA HEPATICA.Saturn: The sixth planet in order from the sun. It is one of the five outer planets of the solar system. Its twelve natural satellites include Phoebe and Titan.Sleep Apnea, Central: A condition associated with multiple episodes of sleep apnea which are distinguished from obstructive sleep apnea (SLEEP APNEA, OBSTRUCTIVE) by the complete cessation of efforts to breathe. This disorder is associated with dysfunction of central nervous system centers that regulate respiration.Frostbite: Damage to tissues as the result of low environmental temperatures.Senecio: A species of toxic plants of the Compositae. The poisonous compounds are alkaloids which cause cattle diseases, neoplasms, and liver damage and are used to produce cancers in experimental animals.Acute Disease: Disease having a short and relatively severe course.Spacecraft: Devices, manned and unmanned, which are designed to be placed into an orbit about the Earth or into a trajectory to another celestial body. (NASA Thesaurus, 1988)Trees: Woody, usually tall, perennial higher plants (Angiosperms, Gymnosperms, and some Pterophyta) having usually a main stem and numerous branches.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Rain: Water particles that fall from the ATMOSPHERE.Cyperaceae: The sedge plant family of the order Cyperales, subclass Commelinidae, class Liliopsida (monocotyledons)EcuadorSolar Activity: Any type of variation in the appearance of energy output of the sun. (NASA Thesaurus, 1994)Animal Migration: Periodic movements of animals in response to seasonal changes or reproductive instinct. Hormonal changes are the trigger in at least some animals. Most migrations are made for reasons of climatic change, feeding, or breeding.Atmosphere: The gaseous envelope surrounding a planet or similar body. (From Random House Unabridged Dictionary, 2d ed)Acid-Base Equilibrium: The balance between acids and bases in the BODY FLUIDS. The pH (HYDROGEN-ION CONCENTRATION) of the arterial BLOOD provides an index for the total body acid-base balance.Sports: Activities or games, usually involving physical effort or skill. Reasons for engagement in sports include pleasure, competition, and/or financial reward.Mouth FloorSwitzerlandPoa: A plant genus of the family POACEAE that contains the Poa p Ia allergen and allergen C KBGP.Sleep: A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility.Population Density: Number of individuals in a population relative to space.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.Snow: Frozen water crystals that fall from the ATMOSPHERE.Hypoxia, Brain: A reduction in brain oxygen supply due to ANOXEMIA (a reduced amount of oxygen being carried in the blood by HEMOGLOBIN), or to a restriction of the blood supply to the brain, or both. Severe hypoxia is referred to as anoxia, and is a relatively common cause of injury to the central nervous system. Prolonged brain anoxia may lead to BRAIN DEATH or a PERSISTENT VEGETATIVE STATE. Histologically, this condition is characterized by neuronal loss which is most prominent in the HIPPOCAMPUS; GLOBUS PALLIDUS; CEREBELLUM; and inferior olives.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.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Regional Blood Flow: The flow of BLOOD through or around an organ or region of the body.Environment, Controlled: A state in which the environs of hospitals, laboratories, domestic and animal housing, work places, spacecraft, and other surroundings are under technological control with regard to air conditioning, heating, lighting, humidity, ventilation, and other ambient features. The concept includes control of atmospheric composition. (From Jane's Aerospace Dictionary, 3d ed)Temazepam: A benzodiazepine that acts as a GAMMA-AMINOBUTYRIC ACID modulator and anti-anxiety agent.Trifolium: A plant genus of the family FABACEAE.Splenic Infarction: Insufficiency of arterial or venous blood supply to the spleen due to emboli, thrombi, vascular torsion, or pressure that produces a macroscopic area of necrosis. (From Stedman, 25th ed)Fontan Procedure: A procedure in which total right atrial or total caval blood flow is channeled directly into the pulmonary artery or into a small right ventricle that serves only as a conduit. The principal congenital malformations for which this operation is useful are TRICUSPID ATRESIA and single ventricle with pulmonary stenosis.YemenChina: A country spanning from central Asia to the Pacific Ocean.Oxyhemoglobins: A compound formed by the combination of hemoglobin and oxygen. It is a complex in which the oxygen is bound directly to the iron without causing a change from the ferrous to the ferric state.Extraterrestrial Environment: The environment outside the earth or its atmosphere. The environment may refer to a closed cabin (such as a space shuttle or space station) or to space itself, the moon, or other planets.Physical Education and Training: Instructional programs in the care and development of the body, often in schools. The concept does not include prescribed exercises, which is EXERCISE THERAPY.Exercise Test: Controlled physical activity which is performed in order to allow assessment of physiological functions, particularly cardiovascular and pulmonary, but also aerobic capacity. Maximal (most intense) exercise is usually required but submaximal exercise is also used.Blood Flow Velocity: A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.Peromyscus: A genus of the subfamily SIGMODONTINAE consisting of 49 species. Two of these are widely used in medical research. They are P. leucopus, or the white-footed mouse, and P. maniculatus, or the deer mouse.Erythropoietin: Glycoprotein hormone, secreted chiefly by the KIDNEY in the adult and the LIVER in the FETUS, that acts on erythroid stem cells of the BONE MARROW to stimulate proliferation and differentiation.Cerebrovascular Circulation: The circulation of blood through the BLOOD VESSELS of the BRAIN.Rest: Freedom from activity.Fetal Hypoxia: Deficient oxygenation of FETAL BLOOD.Disease Vectors: Invertebrates or non-human vertebrates which transmit infective organisms from one host to another.Energy Metabolism: The chemical reactions involved in the production and utilization of various forms of energy in cells.Animal Distribution: A process by which animals in various forms and stages of development are physically distributed through time and space.Oxygen Inhalation Therapy: Inhalation of oxygen aimed at restoring toward normal any pathophysiologic alterations of gas exchange in the cardiopulmonary system, as by the use of a respirator, nasal catheter, tent, chamber, or mask. (From Dorland, 27th ed & Stedman, 25th ed)Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Muscle, Skeletal: A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.Blood Volume: Volume of circulating BLOOD. It is the sum of the PLASMA VOLUME and ERYTHROCYTE VOLUME.KyrgyzstanEnvironment: The external elements and conditions which surround, influence, and affect the life and development of an organism or population.Carbolines: A group of pyrido-indole compounds. Included are any points of fusion of pyridine with the five-membered ring of indole and any derivatives of these compounds. These are similar to CARBAZOLES which are benzo-indoles.Cold Climate: A climate characterized by COLD TEMPERATURE for a majority of the time during the year.Cosmic Radiation: High-energy radiation or particles from extraterrestrial space that strike the earth, its atmosphere, or spacecraft and may create secondary radiation as a result of collisions with the atmosphere or spacecraft.SicilyFresh Water: Water containing no significant amounts of salts, such as water from RIVERS and LAKES.Spatial Analysis: Techniques which study entities using their topological, geometric, or geographic properties.Air Microbiology: The presence of bacteria, viruses, and fungi in the air. This term is not restricted to pathogenic organisms.TajikistanHypercapnia: A clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.Apnea: A transient absence of spontaneous respiration.Body Weight: The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.American Native Continental Ancestry Group: Individuals whose ancestral origins are in the continents of the Americas.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.Hypertrophy, Right Ventricular: Enlargement of the RIGHT VENTRICLE of the heart. This increase in ventricular mass is often attributed to PULMONARY HYPERTENSION and is a contributor to cardiovascular morbidity and mortality.Sheep, Domestic: A species of sheep, Ovis aries, descended from Near Eastern wild forms, especially mouflon.Glycopyrrolate: A muscarinic antagonist used as an antispasmodic, in some disorders of the gastrointestinal tract, and to reduce salivation with some anesthetics.Hemoglobinometry: Measurement of hemoglobin concentration in blood.Cardiovascular Physiological Processes: Biological actions and events that support the functions of the CARDIOVASCULAR SYSTEM.Yin-Yang: In Chinese philosophy and religion, two principles, one negative, dark, and feminine (yin) and one positive, bright, and masculine (yang), from whose interaction all things are produced and all things are dissolved. As a concept the two polar elements referred originally to the shady and sunny sides of a valley or a hill but it developed into the relationship of any contrasting pair: those specified above (female-male, etc.) as well as cold-hot, wet-dry, weak-strong, etc. It is not a distinct system of thought by itself but permeates Chinese life and thought. A balance of yin and yang is essential to health. A deficiency of either principle can manifest as disease. (Encyclopedia Americana)Humidity: A measure of the amount of WATER VAPOR in the air.Climate Change: Any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). It may result from natural factors such as changes in the sun's intensity, natural processes within the climate system such as changes in ocean circulation, or human activities.Dyssomnias: A broad category of sleep disorders characterized by either hypersomnolence or insomnia. The three major subcategories include intrinsic (i.e., arising from within the body) (SLEEP DISORDERS, INTRINSIC), extrinsic (secondary to environmental conditions or various pathologic conditions), and disturbances of circadian rhythm. (From Thorpy, Sleep Disorders Medicine, 1994, p187)Pulmonary Diffusing Capacity: The amount of a gas taken up, by the pulmonary capillary blood from the alveolar gas, per minute per unit of average pressure of the gradient of the gas across the BLOOD-AIR BARRIER.Weather: The state of the ATMOSPHERE over minutes to months.Acceleration: An increase in the rate of speed.Caryophyllaceae: A plant family of the order Caryophyllales, subclass Caryophyllidae, class Magnoliopsida. The species are diverse in appearance and habitat; most have swollen leaf and stem joints.Cardiac Output: The volume of BLOOD passing through the HEART per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with STROKE VOLUME (volume per beat).Bambusa: A plant genus of the family POACEAE. Young shoots are eaten in Asian foods while the stiff mature stems are used for construction of many things. The common name of bamboo is also used for other genera of Poaceae including Phyllostachys, SASA, and Dendrocalamus.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Middle Cerebral Artery: The largest of the cerebral arteries. It trifurcates into temporal, frontal, and parietal branches supplying blood to most of the parenchyma of these lobes in the CEREBRAL CORTEX. These are the areas involved in motor, sensory, and speech activities.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Lactic Acid: A normal intermediate in the fermentation (oxidation, metabolism) of sugar. The concentrated form is used internally to prevent gastrointestinal fermentation. (From Stedman, 26th ed)Hypoxia-Inducible Factor-Proline Dioxygenases: Dioxygenase enzymes that specifically hydroxylate a PROLINE residue on the HYPOXIA-INDUCIBLE FACTOR 1, ALPHA SUBUNIT. They are OXYGEN-dependent enzymes that play an important role in mediating cellular adaptive responses to HYPOXIA.Birds: Warm-blooded VERTEBRATES possessing FEATHERS and belonging to the class Aves.Prevalence: The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.Endemic Diseases: The constant presence of diseases or infectious agents within a given geographic area or population group. It may also refer to the usual prevalence of a given disease with such area or group. It includes holoendemic and hyperendemic diseases. A holoendemic disease is one for which a high prevalent level of infection begins early in life and affects most of the child population, leading to a state of equilibrium such that the adult population shows evidence of the disease much less commonly than do children (malaria in many communities is a holoendemic disease). A hyperendemic disease is one that is constantly present at a high incidence and/or prevalence rate and affects all groups equally. (Last, A Dictionary of Epidemiology, 3d ed, p53, 78, 80)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.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.Reticulocyte Count: The number of RETICULOCYTES per unit volume of BLOOD. The values are expressed as a percentage of the ERYTHROCYTE COUNT or in the form of an index ("corrected reticulocyte index"), which attempts to account for the number of circulating erythrocytes.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.Disease Susceptibility: A constitution or condition of the body which makes the tissues react in special ways to certain extrinsic stimuli and thus tends to make the individual more than usually susceptible to certain diseases.Doping in Sports: Illegitimate use of substances for a desired effect in competitive sports. It includes humans and animals.Blood Circulation Time: Determination of the shortest time interval between the injection of a substance in the vein and its arrival at some distant site in sufficient concentration to produce a recognizable end result. It represents approximately the inverse of the average velocity of blood flow between two points.Remote Sensing Technology: Observation and acquisition of physical data from a distance by viewing and making measurements from a distance or receiving transmitted data from observations made at distant location.Hemodynamics: The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.Population Dynamics: The pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.Madagascar: One of the Indian Ocean Islands off the southeast coast of Africa. Its capital is Antananarivo. It was formerly called the Malagasy Republic. Discovered by the Portuguese in 1500, its history has been tied predominantly to the French, becoming a French protectorate in 1882, a French colony in 1896, and a territory within the French union in 1946. The Malagasy Republic was established in the French Community in 1958 but it achieved independence in 1960. Its name was changed to Madagascar in 1975. (From Webster's New Geographical Dictionary, 1988, p714)Fagaceae: A plant family of the order Fagales subclass Hamamelidae, class Magnoliopsida.Glucose 1-Dehydrogenase: A glucose dehydrogenase that catalyzes the oxidation of beta-D-glucose to form D-glucono-1,5-lactone, using NAD as well as NADP as a coenzyme.Cardiac Complexes, Premature: A group of cardiac arrhythmias in which the cardiac contractions are not initiated at the SINOATRIAL NODE. They include both atrial and ventricular premature beats, and are also known as extra or ectopic heartbeats. Their frequency is increased in heart diseases.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.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)Tanzania: A republic in eastern Africa, south of UGANDA and north of MOZAMBIQUE. Its capital is Dar es Salaam. It was formed in 1964 by a merger of the countries of TANGANYIKA and ZANZIBAR.Tricuspid Atresia: Absence of the orifice between the RIGHT ATRIUM and RIGHT VENTRICLE, with the presence of an atrial defect through which all the systemic venous return reaches the left heart. As a result, there is left ventricular hypertrophy (HYPERTROPHY, LEFT VENTRICULAR) because the right ventricle is absent or not functional.Chronic Disease: Diseases which have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care. (Dictionary of Health Services Management, 2d ed)Sheep: Any of the ruminant mammals with curved horns in the genus Ovis, family Bovidae. They possess lachrymal grooves and interdigital glands, which are absent in GOATS.Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.Linear Models: Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.Plethysmography, Impedance: Recording changes in electrical impedance between electrodes placed on opposite sides of a part of the body, as a measure of volume changes in the path of the current. (Stedman, 25th ed)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.Arteries: The vessels carrying blood away from the heart.VenezuelaPhonocardiography: Graphic registration of the heart sounds picked up as vibrations and transformed by a piezoelectric crystal microphone into a varying electrical output according to the stresses imposed by the sound waves. The electrical output is amplified by a stethograph amplifier and recorded by a device incorporated into the electrocardiograph or by a multichannel recording machine.Aviation: Design, development, manufacture, and operation of heavier-than-air AIRCRAFT.SulfonesInfant Welfare: Organized efforts by communities or organizations to improve the health and well-being of infants.Catecholamines: A general class of ortho-dihydroxyphenylalkylamines derived from tyrosine.Physical Fitness: The ability to carry out daily tasks and perform physical activities in a highly functional state, often as a result of physical conditioning.Camelids, New World: Ruminant mammals of South America. They are related to camels.Elephantiasis: Hypertrophy and thickening of tissues from causes other than filarial infection, the latter being described as ELEPHANTIASIS, FILARIAL.Biodiversity: The variety of all native living organisms and their various forms and interrelationships.Water-Electrolyte Balance: The balance of fluid in the BODY FLUID COMPARTMENTS; total BODY WATER; BLOOD VOLUME; EXTRACELLULAR SPACE; INTRACELLULAR SPACE, maintained by processes in the body that regulate the intake and excretion of WATER and ELECTROLYTES, particularly SODIUM and POTASSIUM.Arterial Pressure: The blood pressure in the ARTERIES. It is commonly measured with a SPHYGMOMANOMETER on the upper arm which represents the arterial pressure in the BRACHIAL ARTERY.Carboxyhemoglobin
List of people who died climbing Mount Everest: Mount Everest, at 8,848 metres (29,029 ft) is the world's highest mountain and a particularly desirable peak for mountaineers. More than 250 people have died trying to climb it.Acclimatization: Acclimatization (UK also acclimatisation; US also acclimation) is the process in which an individual organism adjusts to a gradual change in its environment (such as a change in temperature, humidity, photoperiod, or pH), allowing it to maintain performance across a range of environmental conditions. Acclimation occurs in a short period of time (days to weeks), and within the organism's lifetime (compare to adaptation).In Secret Tibet: In Secret Tibet (In disguise amongst lamas, robbers, and wise men) is a travel book by author Theodore Illion, first published in English in 1937.Hypoxic hypoxia: Hypoxic hypoxia is a result of insufficient oxygen available to the lungs. A blocked airway, a drowning or a reduction in partial pressure (high altitude above 10,000 feet) are examples of how lungs can be deprived of oxygen.Atmospheric-pressure laser ionization: Atmospheric pressure laser ionization is an atmospheric pressure ionization method for mass spectrometry (MS). Laser light in the UV range is used to ionize molecules in a resonance-enhanced multiphoton ionization (REMPI) process.Dan BuckinghamIllegal drug trade in Bolivia: The illegal drug trade in Bolivia is complicated by a longstanding indigenous tradition of using coca leaf for chewing and for coca tea. In an example of the balloon effect, dramatic falls in coca cultivation in the late 1990s saw some cultivation move to Colombia.Manipal Teaching HospitalFlash pulmonary edema: In medicine, flash pulmonary edema (oedema in British English) (FPE), is rapid onset pulmonary edema. It is most often precipitated by acute myocardial infarction or mitral regurgitation, but can be caused by aortic regurgitation, heart failure, or almost any cause of elevated left ventricular filling pressures.Arteriovenous oxygen difference: The arteriovenous oxygen difference, or a-vO2 diff, is the difference in the oxygen content of the blood between the arterial blood and the venous blood. It is an indication of how much oxygen is removed from the blood in capillaries as the blood circulates in the body.Maladaptation: A maladaptation () is a trait that is (or has become) more harmful than helpful, in contrast with an adaptation, which is more helpful than harmful. All organisms, from bacteria to humans, display maladaptive and adaptive traits.Aircraft cabin: An aircraft cabin is the section of an aircraft in which passengers travel. At cruising altitudes of modern commercial aircraft the surrounding atmosphere is too thin for passengers and crew to breathe without an oxygen mask, so cabins are pressurized at a higher pressure than ambient pressure at altitude.List of Royal Air Force aircraft independent flights: This is a list of Royal Air Force independent Flights. An independent Flight is a military administrative structure which is used to command flying units where the number of aircraft is not large enough to warrant a fully fledged squadron.Decompression (diving): The decompression of a diver is the reduction in ambient pressure experienced during ascent from depth. It is also the process of elimination of dissolved inert gases from the diver's body, which occurs during the ascent, during pauses in the ascent known as decompression stops, and after surfacing until the gas concentrations reach equilibrium.Respirometer: A respirometer is a device used to measure the rate of respiration of a living organism by measuring its rate of exchange of oxygen and/or carbon dioxide. They allow investigation into how factors such as age, chemicals or the effect of light affect the rate of respiration.Illegal drug trade in Peru: The illegal drug trade in Peru includes the growing of coca and the shipment of cocaine to the United States. In an example of the balloon effect, dramatic falls in coca cultivation in the late 1990s saw cultivation move to Colombia.DimefoxLampreado: thumb | 250px | right | LampreadoHemoglobin, alpha 2: Hemoglobin, alpha 2 also known as HBA2 is a gene that in humans codes for the alpha globin chain of hemoglobin.Ranunculus abortivus: Ranunculus abortivus is a species of flowering plant in the buttercup family, Ranunculaceae. Its common names include littleleaf buttercup, small-flower crowfoot,Ranunculus abortivus.Irina Khazova: Russia}}Hypocapnia: Hypocapnia or hypocapnea also known as hypocarbia, sometimes incorrectly called acapnia, is a state of reduced carbon dioxide in the blood. Hypocapnia usually results from deep or rapid breathing, known as hyperventilation.BalloonGas analysis: Gas analysis could refer to any of the following:Diuretic: A diuretic is any substance that promotes the production of urine. This includes forced diuresis.Mountaineer Wind Energy Center: Mountaineer Wind Energy Center is a wind farm on Backbone Mountain in Preston and Tucker counties in the U.S.Anthem (The 2002 FIFA World Cup Official Anthem): Anthem (The 2002 FIFA World Cup Official Anthem) by Vangelis and produced and mixed by Takkyu Ishino is the theme song for 2002 FIFA World Cup held in South Korea and Japan. The single was commercially successful in Japan, being certified platinum for 100,000 copies shipped to stores.Hematocrit: The hematocrit (Ht or HCT, British English spelling haematocrit), also known as packed cell volume (PCV) or erythrocyte volume fraction (EVF), is the volume percentage (%) of red blood cells in blood. It is normally 45% for men and 40% for women.Mount Fuji Radar System: The Mount Fuji Radar System is a historic weather radar system located on the summit of Mount Fuji, Japan. It was completed in 1964, and is now recorded on the list of IEEE Milestones in electrical engineering.Uranium mining in Colorado: Uranium mining in Colorado, United States, goes back to 1872, when pitchblende ore was taken from gold mines near Central City, Colorado. The Colorado uranium industry has seen booms and busts, but continues to this day.Shitaye Gemechu: Shitaye Gemechu (born 17 June 1980) is an Ethiopian long-distance runner, who specializes in marathon races. Shitaye was the women's winner of the Rock 'n' Roll Arizona Marathon for the years 2004 - 2006.In-water recompression: In-water recompression (IWR) or underwater oxygen treatment is the emergency treatment of decompression sickness (DCS) of sending the diver back underwater to allow the gas bubbles in the tissues, which are causing the symptoms, to resolve. It is a risky procedure that should only ever be used when the time to travel to the nearest recompression chamber is too long to save the victim's life.PolycythemiaPhysical strength: Strength (physics)}}Harmening High Flyer: The Harmening High Flyer is an American powered parachute that was designed and produced by Harmening's High Flyers of Genoa, Illinois.Cliche, Andre: Ultralight Aircraft Shopper's Guide 8th Edition, page D-7.Pulmonary gas pressures: The factors that determine the values for alveolar pO2 and pCO2 are:Nellcor: Nellcor is a brand of pulse oximetry systems sold by the Medtronic Corporation, following its acquisition of Covidien.List of countries by carbon dioxide emissionsHadley Centre for Climate Prediction and Research: 140px|rightHealth geography: Health geography is the application of geographical information, perspectives, and methods to the study of health, disease, and health care.High-intensity interval training: High-intensity interval training (HIIT), also called high-intensity intermittent exercise (HIIE) or sprint interval training (SIT), is an enhanced form of interval training, an exercise strategy alternating short periods of intense anaerobic exercise with less-intense recovery periods. HIIT is a form of cardiovascular exercise.Amy PetersonLepidium meyenii: Lepidium meyenii (maca) is an herbaceous biennial plant of the crucifer family native to the high Andes of Peru. It was found at the Meseta of BomBom close to Junin Lake in the Andes.Four Seasons Baltimore and Residences: Four Seasons Hotel Baltimore is currently a 22 story highrise hotel complex building which opened on November 14, 2011. The building's construction began back in 2007 and went through several changes.Cadence (cycling): In cycling, cadence (or pedaling rate) is the number of revolutions of the crank per minute; roughly speaking, this is the rate at which a cyclist is pedalling/turning the pedals. Cadence is related to wheel speed, but is a distinct measurement.Interbeat interval: Interbeat interval is a scientific term used in the study of the mammalian heart.Carte Jaune: The Carte Jaune or Yellow Card is an international certificate of vaccination (ICV). It is issued by the World Health Organisation.Healthcare in Austria: The nation of Austria has a two-tier health care system in which virtually all individuals receive publicly funded care, but they also have the option to purchase supplementary private health insurance. Some individuals choose to completely pay for their care privately.Utiaritichthys: Utiaritichthys is a genus of serrasalmid found in the Amazon and Orinoco basins in tropical South America.Pulmonary Hypertension Association: The Pulmonary Hypertension Association (PHA) is a 501(c) organization non-profit support, education, advocacy and awareness association for pulmonary hypertension (PH). It provides information to the public about the illness and acts as a support group for those with the disease, providing medical provider location services and emotional support for those suffering from the illness.Quasiperiodicity: Quasiperiodicity is the property of a system that displays irregular periodicity. Periodic behavior is defined as recurring at regular intervals, such as "every 24 hours".Eli Schwartz: Eliezer (Eli) Schwartz (Hebrew: אליעזר שוורץ) MD, DTMH is an Israeli physician, known for his speciality in tropical diseases and travel medicine. He is a founding member of the International Society of Travel Medicine (ISTM) and served as chair of its Professional Education Committee.Larry LemakList of Copper Country minesRetinal haemorrhageAddis Ababa Fistula HospitalEcosystemBergenia ciliata: Bergenia ciliata ( Sanskrit : Pashanbheda )Controversial Drug Plants By R. Vasudevan NairGoose egg addling: Goose egg “addling” is a wildlife management method of population control for Canada geese and other bird species. The process of addling involves temporarily removing fertilized eggs from the nest, testing for embryo development, terminating embryo development, and placing the egg back in the nest.Pulmonary artery banding: Pulmonary Artery Banding (PAB) was introduced by Muller and Danimann in 1951 as a surgical technique to reduce excessive pulmonary blood flow in infants suffering from congenital heart defects.Muller WH, Dammann JF.Respiratory compensation: Respiratory compensation is a mechanism by which plasma pH can be altered by varying the respiratory rate. It is faster than renal compensation, but has less ability to restore normal values.FasciolosisSaturn A-1: Saturn A-1, studied in 1959, was projected to be the first version of Saturn I and was to be used if necessary before the S-IV liquid hydrogen second stage became available. The first stage, proposed for the Juno V rocket, but finally used for the first Saturn rocket, would propel the Saturn A-1 into space, with the first stage of a Titan I missile continuing the flight and finally, a Centaur C high-energy double-engine third stage could perform a small burn to send a payload into its final orbit, or it can perform a big burn to take a payload out of Earth orbit to other planets.Central sleep apnea: Central sleep apnea (CSA) or central sleep apnea syndrome (CSAS) is a sleep-related disorder in which the effort to breathe is diminished or absent, typically for 10 to 30 seconds, either intermittently or in cycles and is usually associated with a reduction in blood oxygen saturation. It is a collective term referring to two breathing disorders: Cheyne-Stokes respiration and periodic breathing.Kurt DiembergerSenecio madagascariensisRobotic spacecraft: 250px|right|thumb|An artist's interpretation of the [[MESSENGER spacecraft at Mercury]]Peat swamp forest: Peat swamp forests are tropical moist forests where waterlogged soil prevents dead leaves and wood from fully decomposing. Over time, this creates a thick layer of acidic peat.Temporal analysis of products: Temporal Analysis of Products (TAP), (TAP-2), (TAP-3) is an experimental technique for studyingThe Rain Rain Rain Came Down Down Down: "The Rain Rain Rain Came Down Down Down" is a narrative song from the Walt Disney musical film featurette, Winnie the Pooh and the Blustery Day. The song is also incorporated into the 1977 musical film The Many Adventures of Winnie the Pooh which is an amalgamation of three Winnie-the-Pooh featurettes including "Blustery Day".Cladium: Cladium (Fen-sedge, Sawgrass or Twig-sedge) is a genus of large sedges, with a nearly worldwide distribution in tropical and temperate regions. These are plants characterized by long, narrow (grass-like) leaves having sharp, often serrated (sawtooth-like) margins, and flowering stems 1–3 m tall bearing a much-branched inflorescence.Smoking in Ecuador: Smoking in Ecuador is more common among men and younger people. More than half of Ecuadorian smokers desire to quit.Sunspots (economics): In economics, the term sunspots (or sometimes "a sunspot") usually refers to an extrinsic random variable, that is, a random variable that does not affect economic fundamentals (such as endowments, preferences, or technology). Sunspots can also refer to the related concept of extrinsic uncertainty, that is, economic uncertainty that does not come from variation in economic fundamentals.Geolocation software: In computing, geolocation software is used to deduce the geolocation (geographic location) of another party. For example, on the Internet, one geolocation approach is to identify the subject party's IP address, then determine what country (including down to the city and post/ZIP code level), organization, or user the IP address has been assigned to, and finally, determine that party's location.Stratosphere: The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. It is stratified in temperature, with warmer layers higher up and cooler layers farther down.Acid–base reaction: An acid–base reaction is a chemical reaction that occurs between an acid and a base. Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their application in solving related problems.Assunta LegnanteDark FieldsLausanne Marathon: The Lausanne Marathon or Marathon of Lausanne is an annual marathon race held in the Swiss city of Lausanne since 1993. This road running takes place in autumn (October) and the 20 km of Lausanne takes place in spring (April).Poa bulbosa: Poa bulbosa is a species of grass known by the common names bulbous bluegrass or bulbous meadow-grass. It is native to Eurasia and North Africa, but it is present practically worldwide as an introduced species.Non-rapid eye movement sleepThreshold host density: Threshold host density (NT), in the context of wildlife disease ecology, refers to the concentration of a population of a particular organism as it relates to disease. Specifically, the threshold host density (NT) of a species refers to the minimum concentration of individuals necessary to sustain a given disease within a population.Snow pea: The snow pea (Pisum sativum var. saccharatum) is a legume, more specifically a variety of pea eaten whole in its pod while still unripe.Cerebral hypoxiaCheyne–Stokes respirationAortic pressure: Central aortic blood pressure (CAP or CASP) is the blood pressure at the root of aorta. Studies have shown the importance of central aortic pressure and its implications in assessing the efficacy of antihypertensive treatment with respect to cardiovascular risk factors.
(1/1342) Barometric pressures on Mt. Everest: new data and physiological significance.
Barometric pressures (PB) near the summit of Mt. Everest (altitude 8, 848 m) are of great physiological interest because the partial pressure of oxygen is very near the limit for human survival. Until recently, the only direct measurement on the summit was 253 Torr, which was obtained in October 1981, but, despite being only one data point, this value has been used by several investigators. Recently, two new studies were carried out. In May 1997, another direct measurement on the summit was within approximately 1 Torr of 253 Torr, and meteorologic data recorded at the same time from weather balloons also agreed closely. In the summer of 1998, over 2,000 measurements were transmitted from a barometer placed on the South Col (altitude 7,986 m). The mean PB values during May, June, July, and August were 284, 285, 286, and 287 Torr, respectively, and there was close agreement with the PB-altitude (h) relationship determined from the 1981 data. The PB values are well predicted from the equation PB = exp (6.63268 - 0.1112 h - 0.00149 h2), where h is in kilometers. The conclusion is that on days when the mountain is usually climbed, during May and October, the summit pressure is 251-253 Torr. (+info)
(2/1342) Low-temperature sensitivity and enhanced Bohr effect in red deer (Cervus elaphus) haemoglobin: a molecular adaptive strategy to life at high altitude and low temperature.
A study of the functional properties of haemoglobin from red deer (Cervus elaphus) whose habitat varies over a wide range of latitude, was performed. The oxygen-binding properties of the most common haemoglobin phenotype from the species living in Sardinia were examined with particular attention to the effect of pH, chloride, 2, 3-bisphosphoglycerate and temperature. Results indicate that red deer haemoglobin, like all haemoglobins from ruminants so far examined, is characterized by a low intrinsic oxygen affinity, with chloride being its main physiological modulator in vivo. The functional results and the low temperature sensitivity of the oxygen affinity are discussed in the light of the amino acid sequence of closely related ruminant haemoglobins. (+info)
(3/1342) Augmented sympathetic activation during short-term hypoxia and high-altitude exposure in subjects susceptible to high-altitude pulmonary edema.
BACKGROUND: Pulmonary hypertension is a hallmark of high-altitude pulmonary edema and may contribute to its pathogenesis. Cardiovascular adjustments to hypoxia are mediated, at least in part, by the sympathetic nervous system, and sympathetic activation promotes pulmonary vasoconstriction and alveolar fluid flooding in experimental animals. METHODS AND RESULTS: We measured sympathetic nerve activity (using intraneural microelectrodes) in 8 mountaineers susceptible to high-altitude pulmonary edema and 7 mountaineers resistant to this condition during short-term hypoxic breathing at low altitude and at rest at a high-altitude laboratory (4559 m). We also measured systolic pulmonary artery pressure to examine the relationship between sympathetic activation and pulmonary vasoconstriction. In subjects prone to pulmonary edema, short-term hypoxic breathing at low altitude evoked comparable hypoxemia but a 2- to 3-times-larger increase in the rate of the sympathetic nerve discharge than in subjects resistant to edema (P<0.001). At high altitude, in subjects prone to edema, the increase in the mean+/-SE sympathetic firing rate was >2 times larger than in those resistant to edema (36+/-7 versus 15+/-4 bursts per minute, P<0.001) and preceded the development of lung edema. We observed a direct relationship between sympathetic nerve activity and pulmonary artery pressure measured at low and high altitude in the 2 groups (r=0.83, P<0.0001). CONCLUSIONS: With the use of direct measurements of postganglionic sympathetic nerve discharge, these data provide the first evidence for an exaggerated sympathetic activation in subjects prone to high-altitude pulmonary edema both during short-term hypoxic breathing at low altitude and during actual high-altitude exposure. Sympathetic overactivation may contribute to high-altitude pulmonary edema. (+info)
(4/1342) Living at high altitude and risk of sudden infant death syndrome.
OBJECTIVE: To investigate the association between altitude of residence and risk of sudden infant death syndrome (SIDS). METHODS: A retrospective, case control study in the Tyrol, Austria enrolled 99 infants with SIDS occurring between 1984 and 1994, and 136 randomly selected control cases. Data on pregnancy, delivery, child care practice, and socio-demographic characteristics including altitude of residence were collected with a standardised questionnaire. RESULTS: The risk of SIDS increased gradually with increasing altitude of residence. This relation remained independently significant when the analysis was adjusted for gestational age, birth weight, prenatal care, mother's age at delivery, educational level of parents, and cigarette smoking during pregnancy. The prone sleeping position emerged as an obligatory cofactor in this association. In the whole of Austria, a similar trend of association emerged between the average altitudes in the 99 political counties and the rates of SIDS. CONCLUSIONS: This study identified altitude of residence as a significant risk predictor of SIDS, primarily in combination with the prone sleeping position. Respiratory disturbances, reduced oxygen saturation, and lower temperatures at high altitude might explain this association. (+info)
(5/1342) Cough frequency and cough receptor sensitivity to citric acid challenge during a simulated ascent to extreme altitude.
The aim of this study was to determine the frequency of cough and the citric acid cough threshold during hypobaric hypoxia under controlled environmental conditions. Subjects were studied during Operation Everest 3. Eight subjects ascended to a simulated altitude of 8,848 m over 31 days in a hypobaric chamber. Frequency of nocturnal cough was measured using voice-activated tape recorders, and cough threshold by inhalation of increasing concentrations of citric acid aerosol. Spirometry was performed before and after each test. Subjects recorded symptoms of acute mountain sickness and arterial oxygen saturation daily. Air temperature and humidity were controlled during the operation. Cough frequency increased with increasing altitude, from a median of 0 coughs (range 0-4) at sea level to 15 coughs (range 3-32) at a simulated altitude of 8,000 m. Cough threshold was unchanged on arrival at 5,000 m compared to sea level (geometric mean difference (GMD) 1.0, 95% confidence intervals (CI) 0.5-2.1, p=0.5), but fell on arrival at 8,000 m compared to sea level (GMD 3.3, 95% CI 1.1-10.3, p=0.043). There was no relationship between cough threshold and symptoms of acute mountain sickness, oxygen saturation or forced expiratory volume in one second. Temperature and humidity in the chamber were controlled between 18-24 degrees C and 30-60%, respectively. These results confirm an increase in cough frequency and cough receptor sensitivity associated with hypobaric hypoxia, and refute the hypothesis that high altitude cough is due to the inhalation of cold, dry air. The small sample size makes further conclusions difficult, and the cause of altitude-related cough remains unclear. (+info)
(6/1342) Exercise VE and physical performance at altitude are not affected by menstrual cycle phase.
We hypothesized that progesterone-mediated ventilatory stimulation during the midluteal phase of the menstrual cycle would increase exercise minute ventilation (VE; l/min) at sea level (SL) and with acute altitude (AA) exposure but would only increase arterial O2 saturation (SaO2, %) with AA exposure. We further hypothesized that an increased exercise SaO2 with AA exposure would enhance O2 transport and improve both peak O2 uptake (VO2 peak; ml x kg-1 x min-1) and submaximal exercise time to exhaustion (Exh; min) in the midluteal phase. Eight female lowlanders [33 +/- 3 (mean +/- SD) yr, 58 +/- 6 kg] completed a VO2 peak and Exh test at 70% of their altitude-specific VO2 peak at SL and with AA exposure to 4,300 m in a hypobaric chamber (446 mmHg) in their early follicular and midluteal phases. Progesterone levels increased (P < 0.05) approximately 20-fold from the early follicular to midluteal phase at SL and AA. Peak VE (101 +/- 17) and submaximal VE (55 +/- 9) were not affected by cycle phase or altitude. Submaximal SaO2 did not differ between cycle phases at SL, but it was 3% higher during the midluteal phase with AA exposure. Neither VO2 peak nor Exh time was affected by cycle phase at SL or AA. We conclude that, despite significantly increased progesterone levels in the midluteal phase, exercise VE is not increased at SL or AA. Moreover, neither maximal nor submaximal exercise performance is affected by menstrual cycle phase at SL or AA. (+info)
(7/1342) Loss of heterozygosity in pseudoexfoliation syndrome.
PURPOSE: Pseudoexfoliation (PEX) syndrome is characterized by the accumulation of a material of unknown origin in the anterior structures of the eye. Loss of heterozygosity (LOH) in a genetic locus indicates the presence of a gene located in the same region that could be implicated in the development or the progression of a disease. In this study, the occurrence of LOH in tissues involved in PEX and the possible correlation of LOH incidence with clinical parameters were evaluated. METHODS: Twelve iris specimens, 12 anterior capsule specimens, and respective blood samples were obtained from 17 patients with PEX (13 men), who were undergoing glaucoma and cataract surgery. Sixteen anterior capsule specimens and four iris specimens were obtained from 16 patients without PEX. Polymerase chain reaction was used to amplify 10 highly polymorphic microsatellite markers located on chromosomes 1, 7, 9, and 13. RESULTS: Overall, 83.3% (20/24) of PEX specimens and 94.11% (16/17) of patients with PEX had LOH. The highest incidence of LOH was observed in marker D13S175 (41.6%) followed by D7S478 and D7S479 (37.5%). Only three non-PEX specimens displayed LOH. The number of loci lost was directly related to the altitude of the patients' present residence, but the number lost did not differ significantly between the iris and capsule samples. CONCLUSIONS: The occurrence of LOH in tissues involved in PEX implies a genetic role in PEX pathogenesis at a cellu lar level. The correlation of LOH incidence with the altitude of the patient's residence, could indicate an increased susceptibility to UV radiation of the chromosomal regions examined. (+info)
(8/1342) Exaggerated endothelin release in high-altitude pulmonary edema.
BACKGROUND: Exaggerated pulmonary hypertension is thought to play an important part in the pathogenesis of high-altitude pulmonary edema (HAPE). Endothelin-1 is a potent pulmonary vasoconstrictor peptide that also augments microvascular permeability. METHODS AND RESULTS: We measured endothelin-1 plasma levels and pulmonary artery pressure in 16 mountaineers prone to HAPE and in 16 mountaineers resistant to this condition at low (580 m) and high (4559 m) altitudes. At high altitude, in mountaineers prone to HAPE, mean (+/-SE) endothelin-1 plasma levels were approximately 33% higher than in HAPE-resistant mountaineers (22.2+/-1.1 versus 16.8+/-1.1 pg/mL, P<0.01). There was a direct relationship between the changes from low to high altitude in endothelin-1 plasma levels and systolic pulmonary artery pressure (r=0.82, P<0.01) and between endothelin-1 plasma levels and pulmonary artery pressure measured at high altitude (r=0.35, P=0.05). CONCLUSIONS: These findings suggest that in HAPE-susceptible mountaineers, an augmented release of the potent pulmonary vasoconstrictor peptide endothelin-1 and/or its reduced pulmonary clearance could represent one of the mechanisms contributing to exaggerated pulmonary hypertension at high altitude. (+info)