Biomaterial Database

Stochastic description of inert gas exchange. 1979

P K Weathersby, and E E Barnard, and L D Homer, and K G Mendenhall

Data from experiments measuring the rate of uptake and elimination of nonmetabolic gas in living organs are usually analyzed by several exponential time constants or their equivalent half-times (i.e, exponential series analysis). To avoid the limitations of this technique, we have formulated a method that combines analysis by moments of distribution with transfer function techniques, which makes the analysis independent of any mechanistic model. This method is an improvement over previous methods because it allows better comparison of gas exchange experiments and better prediction of gas exchange in the formulation of diver decompression schedules. Measurements of radioxenon uptake and elimination in two areas of a dog are presented. Analysis of the same organ response by both methods showed a fivefold variation in derived exponential time constants compared with less than 10% variation among moment descriptors.

UI	MeSH Term	Description	Entries
D008954	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.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D012119	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 (	Breathing
D001775	Blood Circulation	The movement of the BLOOD as it is pumped through the CARDIOVASCULAR SYSTEM.	Blood Flow,Circulation, Blood,Blood Flows,Flow, Blood
D003665	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.	Bends,Caisson Disease,Caisson Diseases,Disease, Caisson,Diseases, Caisson,Sickness, Decompression
D004285	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)	Canis familiaris,Dog
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013269	Stochastic Processes	Processes that incorporate some element of randomness, used particularly to refer to a time series of random variables.	Process, Stochastic,Stochastic Process,Processes, Stochastic
D014018	Tissue Distribution	Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.	Distribution, Tissue,Distributions, Tissue,Tissue Distributions
D014978	Xenon	A noble gas with the atomic symbol Xe, atomic number 54, and atomic weight 131.30. It is found in the earth's atmosphere and has been used as an anesthetic.