PRINCIPLES OF TRACER METHODOLOGY 



33 



10,000 



8000 

 7000 

 6000 

 5000 



4000 



^ \i^ Composite curve 



u 



100 

 90 

 80 

 70 

 60 

 50 



40 

 30 



20 



10 



Na ^reoA 



N*[Cp) 



Plasma 



b,<040 1^=0.095 



NjT ^reaB 



C„ -1000 = 2n/e -'-^^^^ ^933e-°°^^^ 



1 



10 



25 



30 



15 20 



Time t , min 



Fig. 1-7. Rc\('rsiblo exchange into more than one compartment. Removal of labeled 

 sodium from plasma of dog. [From Alfred Gellhorn, Margaret Merrell, and Robert M. 

 Rankin, The Rate of Transcapillary Exchange of Sodium in Normal and Shocked Dogs, 

 Am. J. Physiol., 142: 407-427 (1944).] 



the linear portion of the curve between 6 and 20 min gives a vakie of 933 

 for the intercept on the ordinate; this represents the value ao. This 

 straight line represents a simple exponential removal curve whose slope 

 is determined by methods previously described to give the exponential 

 constant 0.095, h^. The straight line is subtracted graphically from the 

 original curve to give another straight line that represents the exponential 

 removal to area A. Column 5 gives the values that are plotted to give 



