[Potency of peroral and parenteral administration of Zinc-DTPA for decorporation of 241Am from the gastrointestinal tract]

An effect of cincacine at three doses (25, 150 and 300 mumol/kg) has been studied in rats receiving 241Am citrate intragastrically. The radionuclide was introduced every other day for 2 weeks. The total content was 925 kBq/kg. A cincacine administration leads to limitation of radionuclide accumulation in the major organs of deposition independent of the modes of intake. At gastrointestinal 241Am intake peroral cincacine administration is more effective in limiting this radionuclide accumulation in skeleton but less effective in reduction of its accumulation in liver compared to parenteral cincacine. No reliable dependence of cincacine efficacy on dosage has been revealed. A morphology study of organs has shown that cincacine ingestion at a dose of 150 mumol/kg for 4 weeks and at a dose of 300 mumol/kg for 2 weeks produces a toxic effect on the small intestine mucosa. 25 mumol/kg is the optimum dose and per os administration of higher doses is not expedient.

[Investigation of biologically active supplement Marinid as a prophylactic agent in ecologically unfavorable territory]

Physicochemical investigation of the biologically active supplement Marinid has been carried out. Biological accessibility of iodine containing in Marinid has been determined. About 60 micrograms of iodine can be assimilated by thyroid from one 0.5 g Marinid tablet. Daily iodine need for groups of different age can be satisfied by 1-4 tablets. Marinid reduces 90Sr resorption from gastrointestinal tract by 20-40%.

[Study of the influence of peroral zincacin on the removing of ingested Americium]

Effect of different cincacine doses was studied in rats ingesting americium citrate during 2 weeks. As a result new data showing the possibility and efficacy of per oral cincacine administration at americium intake into digestive tract have been obtained. Dose dependence of cincacine efficacy has been stated for per oral 241Am intake. Preparation administration at a dose of 25 mumol/kg reduces amount of 241Am in skeleton, liver and kidney by 93, 90 and 33%, respectively and is optimum for radionuclide removal from the body and for the prevention of its deposition in organs. Digestive system organs and kidney structure at cincacine administration at a dose of 150 and 300 mumol/kg) to the rats ingesting 241Am have been studied.

[Study of 137Cs transfer to the rat offspring with breast milk and a modifying effect of ferrocene on this process]

137Cs transfer to the lactating rats' offspring has been investigated following daily administration of the radionuclide to the females. Certain patterns have been established for 137Cs accumulation dynamics in the female rats and their progeny during 30 days of suckling. Radiocaesium accumulation multiplicity in both female rats and offspring, as well as absorbed dose formation and a modifying effect of ferrocinum on these processes have been studied.

[Study of 137Cs transfer across the placenta to the rat fetuses and effect of ferrocin on these processes]

The 137Cs placental transfer to the fetuses was studied using a daily oral 137Cs administration to pregnant rats. At day 19 of gestation, the fetuses receive 0.8% of the amount administered to the female. A daily application of ferrocinum reduces the 137Cs content of the female body by 82-84% and decreases the fetal accumulation down to 0.14%.

[The effect of algisorb on the level of the accumulation of zirconium, ruthenium, iodine and cesium radioactive isotopes in the body of rats]

The sorption effect of Algisorbum has been studied in rats following single and multiple intragastric administration. Algisorbum doses of 250-2000 mg/kg decrease the absorption of 106Ru and 95Zr by 50%, that of 137Cs by 15% and have no effect on 131I absorption. Application of a complex of agents to protect the body from nuclear fission products is discussed.

[Effect of algisorb on decontamination of milk contaminated with 90Sr]

The possibility of algisorb application for decontamination of milk contaminated with 90Sr has been investigated. Added to milk algisorb efficiently fixes radionuclide, giving an insoluble complex alginate-Sr. Administration of this milk has prevented 90Sr absorbtion and accumulation in the skeleton to the extend depending on the sorbent dose.

[The protective action of calcium alginate in chronic 90Sr uptake into the body]

Strontium 90 was given to rats with the diet over a period of 3 months. Administration of a modified calcium alginate reduced 90Sr deposition in the skeleton by 70-90%. No changes in the digestive organs were observed throughout the above period.

[Percutaneous resorption of cesium-137 and strontium-89 in alkali solutions and inactivation of the burned surface]

Experiments on white rats studied percutaneous resorption of 137Cs and 89Sr during their skin application in the form of 10 per cent and 40 per cent solutions of NaOH. The study also involved deactivation of the contaminated skin by means of traditional means of first aid recommended for alkali burn and the application of 5 per cent solution of boric acid with the addition of some detergent or 10 per cent solution of sodium hexametaphosphate. The dependence of deactivation efficacy on the time of beginning sanitary treatment, decontamination procedure and alkali concentration was established.

[Effect of liposome-encapsulated pentacin on plutonium-239 excretion]

A study was made of the influence of pentacin, encapsulated in liposomes, on the excretion of monomeric plutonium-239 from dogs and albino rats. Pentacin in a liposomal form, in comparison with free pentacin, increased the excretion of plutonium in urine from a dog body by 23.5% when administered in 24 h, and by 28% when administered in 20 days; in rats, the excretion increase made 40% after the administration in 30 or 45 days.

[Removal of monomeric 239Pu from bones and liver by liposome-encapsulated pentacin]

Dependence of monomeric 239Pu removal from the liver and skeleton by liposome-encapsulated pentacine on dose and concentration of encapsulated chelate was studied in rats. It has been shown that the liposome-encapsulated pentacine (LP) removed 1.5-2.5 times as much 239Pu as free chelate (FP). Dose-effect dependences were logarithmic. The distinction between LP and FP in 239Pu removal from the liver was maximum when chelate had been used in a dose of 50 mumol/kg, with the dose effect upon injection in a large number of liposomes (200 mumol of lipids/kg) being 1.8 times as high as upon injection in smaller number of liposomes (50 mumol/kg). LP doses varying from 100 to 400 mumol/kg, there were no differences between two types of LP; with a LP dose of 400 mumol/kg its action is a bit stronger than that of the chelate. The distinction between LP and FP in 239Pu removal from the skeleton is the greatest with chelate doses exceeding 100 mumol/kg. The use of liposomes in combination with concentrated chelate solution is more effective. Possible interpretation of the features revealed are discussed.

[Efficacy of polymeric 239Pu removal by liposome-encapsulated pentacin]

Liposome-incapsulated pentacine (DTPA) removes intracellular polimeric 239Pu and colloidal hydroxide of polymeric 239Pu from a rat body in the amounts 2- and 4 times, respectively, exceeding those eliminated by free DTPA. However the amount of 239Pu removed decreases sharply with increasing 239Pu hydrolysation and polymerization. It is concluded that the effectiveness of 239Pu removal depends on the physico-chemical status of the radionuclide and its interaction with the biosubstrate rather than on the amount of DTPA entering the cells.

[14C-pentacin pharmacokinetics in percutaneous uptake]

The authors studied the quantitative mechanisms of percutaneous administration and elimination from the body of Na3Ca-14C-diethylene triaminopentacetic acid applied to the skin in 50% dimethyl sulfoxide or in aqueous solution. The data on the time course of the content of the labeled drug in the skin, blood, skeleton, liver, kidneys and urine of rats are provided.

[Acceleration of the excretion of monomeric 239Pu-citrate from the body as effected by pentacyne encapsulated in liposomes]

Liposomes, obtained by a modified procedure involving reverse phases, contained 2-3-times more 14C-pentacyne than the multilayer Banchem;s liposomes. Efficiency of pentacyne encapsulated in liposomes was higher, as compared with a non-encapsulated preparation in studies of urinary excretion of monomeric 239Pu-citrate in rats. Liposomal pentacyne increased most effectively the rate of the radionuclide excretion from liver tissue and skeleton as compared with the action of non-encapsulated complex-forming agent; as a result of which the radionuclide was excreted from liver tissue at a 1.6-2-times and from skeleton--with the 1.4-times higher rates. The both preparations increased the 239Pu excretion with urine and feces. The liposomal pentacyne accelerated an additional excretion of the nuclide with urine.