Four experiments were performed in which two subjects on two occasions drank approximately 1 pc radon plus daughters in 100 ml of water. Measurements on radon loss in expired air, whole body Radium C content, and radon in the blood permit the calculation of an (MPC), of 2.0 x lo-* pc/ml for occupational exposure. This is based on the stomach as the critical organ, but doses to the lung, kidney, and liver are estimated.
This is the report of a study on the suitability of using measurements of certain isotopes in tooth to estimate levels of the same isotopes in bone. Human tooth, jaw, tibia shaft, calvarium, femur head, and rib from thirteen autopsies were analyzed for 226Ra, zloPb and stable calcium. The degree of uniformity among subjects of the tooth-bone ratio for each type of bone was examined by rank-difference correlation. The calculated coefficients were consistent with the existence of a high positive correlation between tooth and bone burdens of the isotopes measured. Regression analysis using our data as a calibration set led to the prediction that in future sampling when tooth is measured at or above the presently reported mean level for 226Ra, the mean bone value will lie within approximately &SO% of the tooth value at the 95% confidence level. Lead-2 10 level predicted for bone is subject to larger error and is more dependent on the bone type to which the tooth level is referred.
Three female adult dogs were injected intravenously with single doses of radium-226 chloride ranging from 20 to 40 µc. Periodic sampling of blood with added heparin and of urine using a bladder catheter were performed for total elapsed times of from 1 week to 21 weeks. Analyses were made of radium in the plasma, the plasma ultrafiltrate and in the urine. Creatinine was determined in plasma and urine. Radium clearance (average = 1.6 ml/min.), creatinine clearance (average = 46 ml/min.), percentage of the plasma radium which is ultrafilterable (average = 70%), and percentage of the ultra-filtrate which is resorbed (average = 95.3%) have been calculated on a basis of the data obtained. Comparing these values for radium with other comparable published values for strontium and calcium it is inferred that the differences in urinary excretion of these materials is principally caused by differences in resorption in the kidney tubules.
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