190 



G. D. McPherson 



Methods 



Methods are described in detail elsewhere (McPherson, 1965). The ten cases 

 studied are listed in Table 1. Except for cases H3 and H5, all were active children 



Table 1. Children studied using ^*^Ca as a tracer 



Case 

 No. 



Age 

 (years) 



AVeifiht 

 (ka) 



Osteogenesis imperfecta tarda; healing 



fracture of the femur; confined to bed. 



Meningomyelocoele; soft tissue surgery 



of feet. 



Bilateral Legg-Perthes disease ; confined 



to bed. 



Post-polio paresis of leg; soft tissue 



surgery. 



Mild spastic paraplegia; soft tissue 



surgery. 



Mild spastic paraplegia; soft tissue 



surgery. 



Congenital hypoplasia of leg muscles 



possibly post-polio ; soft tissue surgery. 



Mild spastic paraplegia; soft tissue 



surgery. 



Mild spastic hemiplegia; soft tissue 



surgery. 



Mild spastic quadriplcgia ; soft tissue 



surgery. 



without evidence of metabolic bone disease. Following the collection of a control 

 urine sample for determination of the pre-injection abundance of ''^Ca, each child 

 received an intravenous injection of 4 milligrams of ■*'^Ca as CaCU in 2 cc. of sterile 

 water. At the 39. /"/o enrichment level used, the total dose of element was 10 mg; it 

 was injected slowly over one minute. Following the injection period, timed urine 

 samples were collected at the normal voiding times of the children and pooled to 

 give six to twelve hour collections in the first three days followed by 24 hour 

 collections for up to ten days. 



Calcium was isolated from each urine sample by double oxalate precipitation 

 followed by ashing to give calcium carbonate. Approximately 25 milligrams of 

 calcium carbonate from each sample were placed in a small sealed polyethelene 

 capsule and exposed to a neutron flux of 3X10*3 neutrons/cm^/sec. for a period of 

 one or two minutes at the Union Carbide Research Reactor, Tuxedo Park, New York. 

 Five minutes after irradiation the ''^Ca in the samples was measured by gamma 

 scintillation spectrometry and related to the '^^Ca content of standards irradiated 

 under the same conditions. After a one week delay to reduce activity, the samples 

 were dissolved in 1. N HCl and the total calcium content of each sample and 

 standard was determined by a direct recorded EDTA titration method. The abun- 

 dance of '^^Ca in each sample was expressed as a percentage of the normal abundance 

 in standards. Increased abundance levels in each sample were related to the total dose 

 of ■'^^Ca to give specific activity as percent dose ^^Ca per gram calcium. 



