Body Water
Fluids composed mainly of water found within the body.
Water
Deuterium Oxide
The isotopic compound of hydrogen of mass 2 (deuterium) with oxygen. (From Grant & Hackh's Chemical Dictionary, 5th ed) It is used to study mechanisms and rates of chemical or nuclear reactions, as well as biological processes.
Body Fluid Compartments
The two types of spaces between which water and other body fluids are distributed: extracellular and intracellular.
Indicator Dilution Techniques
Water Supply
Deuterium
Body Composition
Oxygen Isotopes
Stable oxygen atoms that have the same atomic number as the element oxygen, but differ in atomic weight. O-17 and 18 are stable oxygen isotopes.
Dehydration
The condition that results from excessive loss of water from a living organism.
Radioisotope Dilution Technique
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.
Potassium Radioisotopes
Fresh Water
Water containing no significant amounts of salts, such as water from RIVERS and LAKES.
Water-Electrolyte Imbalance
Disturbances in the body's WATER-ELECTROLYTE BALANCE.
Bromides
Salts of hydrobromic acid, HBr, with the bromine atom in the 1- oxidation state. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Extracellular Space
Interstitial space between cells, occupied by INTERSTITIAL FLUID as well as amorphous and fibrous substances. For organisms with a CELL WALL, the extracellular space includes everything outside of the CELL MEMBRANE including the PERIPLASM and the cell wall.
Water Pollution
Contamination of bodies of water (such as LAKES; RIVERS; SEAS; and GROUNDWATER.)
Water Purification
Any of several processes in which undesirable impurities in water are removed or neutralized; for example, chlorination, filtration, primary treatment, ion exchange, and distillation. It includes treatment of WASTE WATER to provide potable and hygienic water in a controlled or closed environment as well as provision of public drinking water supplies.
Body Weight
Skinfold Thickness
The measurement of subcutaneous fat located directly beneath the skin by grasping a fold of skin and subcutaneous fat between the thumb and forefinger and pulling it away from the underlying muscle tissue. The thickness of the double layer of skin and subcutaneous tissue is then read with a caliper. The five most frequently measured sites are the upper arm, below the scapula, above the hip bone, the abdomen, and the thigh. Its application is the determination of relative fatness, of changes in physical conditioning programs, and of the percentage of body fat in desirable body weight. (From McArdle, et al., Exercise Physiology, 2d ed, p496-8)
Dielectric Spectroscopy
A technique of measuring the dielectric properties of materials, which vary over a range of frequencies depending on the physical properties of the material. The technique involves measuring, over a range of frequencies, ELECTRICAL IMPEDANCE and phase shift of an electric field as it passes through the material.
Water Deprivation
The withholding of water in a structured experimental situation.
Neutron Activation Analysis
Anthropometry
Water Pollutants, Chemical
Urea
Water Pollutants
Substances or organisms which pollute the water or bodies of water. Use for water pollutants in general or those for which there is no specific heading.
Thirst
A drive stemming from a physiological need for WATER.
Extracellular Fluid
Adipose Tissue
Specialized connective tissue composed of fat cells (ADIPOCYTES). It is the site of stored FATS, usually in the form of TRIGLYCERIDES. In mammals, there are two types of adipose tissue, the WHITE FAT and the BROWN FAT. Their relative distributions vary in different species with most adipose tissue being white.
Methenamine
Sodium Compounds
Inorganic compounds that contain sodium as an integral part of the molecule.
Plasma Volume
Volume of PLASMA in the circulation. It is usually measured by INDICATOR DILUTION TECHNIQUES.
Body Height
Steroid Metabolism, Inborn Errors
Aquaporin 2
Aquaporin 2 is a water-specific channel protein that is expressed in KIDNEY COLLECTING DUCTS. The translocation of aquaporin 2 to the apical PLASMA MEMBRANE is regulated by VASOPRESSIN, and MUTATIONS in AQP2 have been implicated in a variety of kidney disorders including DIABETES INSIPIDUS.
Antipyrine
An analgesic and antipyretic that has been given by mouth and as ear drops. Antipyrine is often used in testing the effects of other drugs or diseases on drug-metabolizing enzymes in the liver. (From Martindale, The Extra Pharmacopoeia, 30th ed, p29)
Bromine
Peritoneal Dialysis
Potassium
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
Water Loss, Insensible
Loss of water by diffusion through the skin and by evaporation from the respiratory tract.
Models, Biological
Absorptiometry, Photon
A noninvasive method for assessing BODY COMPOSITION. It is based on the differential absorption of X-RAYS (or GAMMA RAYS) by different tissues such as bone, fat and other soft tissues. The source of (X-ray or gamma-ray) photon beam is generated either from radioisotopes such as GADOLINIUM 153, IODINE 125, or Americanium 241 which emit GAMMA RAYS in the appropriate range; or from an X-ray tube which produces X-RAYS in the desired range. It is primarily used for quantitating BONE MINERAL CONTENT, especially for the diagnosis of OSTEOPOROSIS, and also in measuring BONE MINERALIZATION.
Nutrition Disorders
Water Movements
Water Softening
Sodium
Chironomidae
Peritoneal Dialysis, Continuous Ambulatory
Portable peritoneal dialysis using the continuous (24 hours a day, 7 days a week) presence of peritoneal dialysis solution in the peritoneal cavity except for periods of drainage and instillation of fresh solution.
Ileostomy
Densitometry
Kidney Failure, Chronic
The end-stage of CHRONIC RENAL INSUFFICIENCY. It is characterized by the severe irreversible kidney damage (as measured by the level of PROTEINURIA) and the reduction in GLOMERULAR FILTRATION RATE to less than 15 ml per min (Kidney Foundation: Kidney Disease Outcome Quality Initiative, 2002). These patients generally require HEMODIALYSIS or KIDNEY TRANSPLANTATION.
Plethysmography, Impedance
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.
Renal Dialysis
Therapy for the insufficient cleansing of the BLOOD by the kidneys based on dialysis and including hemodialysis, PERITONEAL DIALYSIS, and HEMODIAFILTRATION.
Basal Metabolism
Heat production, or its measurement, of an organism at the lowest level of cell chemistry in an inactive, awake, fasting state. It may be determined directly by means of a calorimeter or indirectly by calculating the heat production from an analysis of the end products of oxidation within the organism or from the amount of oxygen utilized.
Blood Volume
Volume of circulating BLOOD. It is the sum of the PLASMA VOLUME and ERYTHROCYTE VOLUME.
Isotope Labeling
Energy Metabolism
Reference Values
Regression Analysis
Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.
Hematocrit
Aquaporins
A class of porins that allow the passage of WATER and other small molecules across CELL MEMBRANES.