Preliminary reports were recently published from this laboratory on the metabolism of intravenously administered radiostrontium and on the effect of calcium upon strontium excretion in man (1, 2). The absorption, the digestive juice excretion and tissue retention have been studied following the oral and intravenous administration of Sr85. Furthermore, the metabolism of orally administered radiostrontium has been compared with that of radiocalcium in the same patients (3,4). These data form the basis of this communication. MATERIALS AND METHODSThe six patients listed in Table I Sr' is a carrier-free isotope5 produced by bombardment of rubidium!. It is a pure 'y-emitter, its energy is 0.51 mev. and its half-life is 65 days. The radioactivity of duplicate samples of plasma, urine and stool was measured in a well-type scintillation counter. The stability of the counting arrangement was checked daily against a uranium standard. The statistical counting error varied: in the initial phases of the experiment sufficient counts were taken to keep the probable error within 2 per cent. In later phases, counting rates were lower, and it was not feasible to maintain this precision, so that counting errors as high as 5 per cent were incurred. Standards were prepared for each patient at the time of administration of the isotope by delivering the same dose into a volumetric flask; appropriate dilutions were then prepared for counting. The standards were counted along with each set of experimental samples, thereby correcting for the decay of the isotope.The radioactivity was determined on 2 to 5 ml. of plasma obtained 5, 15 and 30 minutes and 1, 4, 8 and 24 hours after the ingestion or injection of the isotope. Thereafter, plasma was obtained every morning in the post-absorptive state during the first week of each study and 2 to 3 times per week thereafter. The plasma radioactivity was calculated for the total plasma volume which was determined for each patient using T-1824 dye (6). The urinary output was separated on the day of the isotope administration in fractions at 1, 4, 8 and 24 hours. On the subsequent days, the 24-hour urine output was collected. Aliquots of 2 to 5 ml. of urine were used for radio-assays. Each stool specimen was collected separately, water was added to obtain a homogeneous mixture in a Waring blendor. The weight of the homogenate was determined and aliquots of 4 to 5 gm. were assayed in the scintillation counter. Multiple analyses of such aliquots indicated homogeneous distribution of the isotope. Since the radioactivity of the stool specimens was high after the ingestion of the tracer, these specimens were counted in a bismuth cathode y-counter. The radioactivity was determined on the total stool homogenate and on several water rinses of the Waring blendor using Marinelli beakers.Two patients (2 and 6, Table I) also received an oral tracer of Ca prior to the administration of oral Sr'.
Providing services closer to the population is a rational economic option for the reform of the Hungarian cervical cancer screening program. The other policy aspects of this development, human resource need, stakeholders' interests, organizational aspects, and attitude of the target population need to be carefully considered.
Ethylenediamine tetra-acetic acid (EDTAA) forms soluble complexes with divalent and trivalent metallic ions (1). This chelation was found to be preferential and depends on the pH of the solution. The binding power of this agent for metals is so great that once the metal is chelated it cannot be precipitated by the common precipitating agents.Calcium was shown to form a complex with EDTAA at a pH above 6.5. With increasing hydrogen ion concentration, dissociation occurs and is complete at pH 5. The ability of EDTAA to form complexes with calcium, magnesium, lead and other metals has been studied in uitro and in vivo (2a, b; 3a, b, c, d; 4a, b,). Rapid intravenous injection of the di-sodium salt of EDTAA (diNa-EDTA) into rabbits lowered the serum calcium precipitously to levels causing tetany; these changes could be reversed by the intravenous administration of calcium salts. On the other hand, slow intravenous injection of large quantities of this agent caused no significant decrease of the serum calcium nor any untoward effects (2a). The pharmacological properties of this agent were studied in animals (3c), and its effects upon coagulation were investigated (2b).This agent was investigated in man for the applicability of the above results obtained experimentally. An agent capable of disturbing calcium homeostasis by altering the serum calcium level would be a useful tool of investigation of mineral metabolism. It may also be of therapeutic value in states of deranged calcium metabolism. A comparison of the metabolic effects of the sodium salt with that of the calcium salt of EDTAA (di-NaCa-EDTA) appeared of interest. The latter does not interfere with calcium homeostasis and yet can exchange its calcium with endogenous ionized
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