Joseph Rivera

EFFECT OF INTRAVENOUS CALCIUM AND OF ORALLY ADMINISTERED AMMONIUM CHLORIDE ON STRONTIUM-90 EXCRETION IN MAN.

In investigations of the metabolism of Sr90 (1) and of the effect of agents that may increase the excretion of Sr90 and lower the body burden, the short-lived isotope Sr85 has proved useful as a tracer for Sr90 (2-8). However, agents that are effective in removing recently administered Sr85 in man may be ineffective in removing Sr90 that has been ingested with the diet during long and continued exposure, as the Sr85 and the Sr90 may be deposited at different sites of the skeleton. It had previously been shown that intravenously administered calcium and orally administered ammonium chloride were effective in increasing Sr85 excretion in man (2, 3). The present communication reports the effects of these agents on the enhancement of excretion of Sr90 ingested with the diet.

STRONTIUM-90 METABOLISM DURING LOW STRONTIUM-90 INTAKE IN MAN

Balance studies of Sr90 have been previously performed in this laboratory under controlled dietary conditions in normal young adults (1). In these studies, the Sr90 intake was relatively high, since the diet was supplemented with milk. Tlle high fecal excretion of Sr90 indicated that the major portion of the ingested Sr90 passed unabsorbed through the intestine. The true absorption and the endogenous excretion of Sr90 could not be determined accurately, however, because of the previous intake of Sr90. Subsequently, a similar investigation was carried out during low calcium and low Sr90 intake in a group of young healthy adults of similar age group in order to obtain information on the effect of the previous Sr90 intake on the urinary and intestinal Sr90 excretion and on the comparative intestinal absorption of Sr90 during low and high Sr90 intake. The data obtained in the studies performed during low Sr90 intake are reported in this communication.

Distribution of strontium-90 in a 1959 wheat sample.

At least 22 percent of the strontium-90 found in a sample of wheat harvested in 1959 was due to direct deposition. Twenty-seven percent of the total strontium-90 content of this wheat sample was contained in the outermost bran layer.

Effect of orally and intravenously administered stable strontium on 90 Sr metabolism in man.

The effect of orally and of intravenously administered stable strontium on90 Sr metabolism was investigated in man under strictly controlled dietary conditions. The oral dose of stable strontium av...

Effect of low and high calcium intake on Sr90 metabolism in adult man

Balances of Sr90 have been determined in man under constant dietary conditions during low and high calcium intake but during a similar intake of Sr90. Ten patients were studied during low calcium intake (average 213 mg Ca/day) and 10 patients during high calcium intake (average 1718 mg Ca/day), the latter being attained by adding calcium gluconate tablets to the constant low calcium diet. The average Sr90 intake was similar during low and high calcium intake, 4.6 pCi/day and 5.7 pCi/day, respectively. The average Sr90 balance was slightly more negative during high calcium intake, −0.36 pCi/day, than during low calcium intake, −0.01 pCi/day, however this difference was not significant. Also, there was no significant difference between the percent net absorption of Sr90 during the intake of the low and high calcium diet, 12.3 % versus 6.5% of the Sr90 intake, respectively. The Sr90/Ca ratios of the diet, urine and stool were determined and the Observed Ratios (O.R.) were calculated. The Sr90/Ca ratios of stool/diet were less variable than the Sr90/Ca ratios of urine/diet during the intake of different levels of calcium. Since the Sr90/Ca ratio of stool was similar to the Sr90/Ca ratio of the diet during both low and high calcium intake, the fecal Sr90/Ca ratio can be used for the estimation of the dietary Sr90 intake.

Some Aspects of the Effects of Age and of Calcium Intake on Strontium-90 Metabolism in Man

A comparison of some aspects of %r metabolism of young adults and of persons of the older group has been made. These studies have been performed during both low and high calcium intake under constant dietary conditions. The data indicates that age and calcium intake affect the discrimination between strontium and calcium by the body. The usefulness of the Observed Ratios (O.R.) of urine/diet and of stool/diet for the calculation of the W r content of the diet in the two age groups during different dietary intake levels of calcium has been described.

Health and Safety Laboratory Fallout Program Quarterly Summary Report, June 1, 1965-September 1, 1965

Report documenting radioactive fallout across the world, including material in the atmosphere, on land, and that has deposited into food and water supplies.