RAREFYING DISEASE OF THE SKELETON 



80 



393 



20 



O EXCRETA ASSAYS 



A TOTAL BODY COUNTING 



10 15 



DAYS POST INJECTION 



Fig. 4. Graph showing the rate of excretion of Sr*-"' in Case No. 7, as meas- 

 ured both by the percentage of the close detected by the total body counting 

 technic, and by direct radio assay of total vuinary and fecal output. The results 

 of the two methods are entirely comparable and equally accurate. 



Carlssen-Lindquist calculations were not completed in this case be- 

 cause of mechanical failure of the coimting equipment during the 

 period of the balance study. 



Tetracycline labeling and biopsy. Oxytetracycline was infused 

 intravenously in a dose of 1.0 gm per liter of 0.9 per cent solution 

 on the 5th and 20th days of the control period and again on the 

 50th day. A biopsy was performed on the upper end of the tibia at 

 the conclusion of this studv on the 50th dav. The thickness of the 

 cortex, measured with the aid of a micrometer, was 0.6 mm or 50 

 per cent of that of young adult women. On this basis, assuming that 

 the thickness of the cortex of the upper tibia reflects the density of 

 the whole skeletal system ( Lindahl and Lindgren, 1962 ) , the skele- 

 ton in this patient weighed approximately 5.6 kg. The spaces be- 

 tween the tetracycline lines, considering the 30- versus the 15-day 

 interval, indicate no increase in bone formation rate (Fig. 5A). 



On the histological level, in the low-power magnification with the 

 light microscope, the bone that persists (in Case No. 7) was laid 

 down in the normal configuration and had the appearance of normal 



