Body compartment changes in sick children.
Our studies showed that there are important changes in body composition in children in response to dieting and refeeding. Similarly, we showed changes in body composition in response to renal transplantation, which would be expected to restore more normal homeostasis, but in its early phases changes in body composition are complicated by the use of high doses of drugs, notably steroid. Some of the changes in body composition can be predicted from changes in weight but the majority cannot. Relatively simple measurements like the four skinfolds as a means of determining body fat are surprisingly accurate, except in extremely obese subjects. Similarly, the measurements of fat free body mass are useful. However, this measurement does not discriminate changes within fat free body mass in the proportions of body cell mass versus extracellular mass. Similarly, none of these measurements provide any information regarding the composition of body cell mass with regard to its potassium and protein content (as reflected by total body nitrogen). The main drawback with total body nitrogen measurements is the radiation exposure. Thus, we have had to limit the inclusion of total body nitrogen measurements. It has been estimated that two total body nitrogen measurements provide a gonadal dose of radiation roughly equivalent to that experienced by an individual living in a large North American city, that means 30 to 50 mREM per each total body nitrogen measurement. It becomes ethically possible then to carry out nitrogen measurements where it can be argued that their measurement is essential in monitoring the safety and well being of the subject; or alternatively if the subject's life expectancy is limited.(ABSTRACT TRUNCATED AT 250 WORDS)
Pencharz
P B
PB
Hospital for Sick Children, Toronto, Canada.
Vaisman
N
N
Azcue
M
M
Stallings
V A
VA
D000293:Adolescent; D000328:Adult; D000856:Anorexia Nervosa / Q000503:physiopathology*; D001823:Body Composition; D001825:Body Fluid Compartments / Q000502:physiology*; D001834:Body Water / Q000737:chemistry; D002648:Child; D003550:Cystic Fibrosis / Q000503:physiopathology*; D006801:Humans; D016030:Kidney Transplantation / Q000502:physiology*; D009584:Nitrogen / Q000032:analysis; D009765:Obesity / Q000503:physiopathology*; D010103:Oxygen Isotopes; D011188:Potassium / Q000032:analysis; D015431:Weight Loss
D010103:Oxygen Isotopes; D009584:Nitrogen; D011188:Potassium